Yard & Garden: May 29, 2020

This is the Q&A for the Yard and Garden show for May 29, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the show has tomato plants that now is developing “skinny” leaves. What is wrong with them?

A. The leaves are skinny and deformed. This is likely from herbicide drift, it is hard to say for sure without seeing the plants, but it sounds most like herbicide drift. This has started to become a problem again this year due to the change in weather. As we warm up, we see more problems with 2,4-D and dicamba products that turn to a gas and move to non-target plants. Tomatoes are very sensitive to drift from 2,4-D or Dicamba products. They should grow out of the damage, however because we don’t know exactly what product hit these tomatoes there is no way to know for sure when the product will be out of the tomatoes. I can’t say when or if these tomato plants will be safe for consumption this year.

2. This caller has a very large hosta. When can it be divided?

A. Early spring is the best time to divide hostas, once they have emerged from the ground but before the heat of the summer. It might be a little late to divide the plants this year due to the hot weather expected next week. If they are divided now, be sure to keep them well watered.

3. When can oaks and maples be pruned?

A. The new pruning recommendations show that pruning is best if done in late spring, so late May to early June for Nebraska. Now would be a good time for most trees, however, oaks are susceptible to oak wilt if pruned during the summer months. It is best to wait until fall, September or October, to prune oak trees to avoid this disease. Maples, can have a heavy sap flow in the spring, they can be pruned now, but may leak sap, sometimes large quantities. They would be better to prune in the fall also.

4. A caller was going to use Grass-B-Gon on some weeds she recently hand-pulled to reduce the hand-pulling in the future. How long should the regrowth be before she applies the grass killing product to her landscape beds?

A. As long as you start to see some new, green regrowth, the product should work. According to the label, it should be applied anytime weeds are actively growing, which would be when you see them green up again around your landscape plants.

5. This caller is on her second round of planting tomatoes and they are turning yellow again. She planted the first in late April and then again recently. In the new planting one plant is starting to turn yellow. She is using straw mulch on most of the plants but is using grass mulch on the one plant that is turning yellow. What is wrong with her plants?

A. The first round of plants were planted too soon and we saw quite a bit of cold weather later in the season this year than many other years. She did cover the plants on the sides, but left the top exposed. Frost would have settled down onto the plants and killed them. The new plants are doing fine except the one plant that has grass clippings on it. The lawn has been treated with broadleaf weed control as well as crabgrass control this year. The labels will tell you not to use the clippings on the garden for the season or for a period of time. If that isn’t being followed and this is the one plant that is looking bad, I would assume that the grass clippings are the problem. Be sure to use clean grass clippings or use straw for all of the plants.

6. A caller pulled 3 mature barberry bushes with a pickup truck and then decided to replant them after all. What should be done to keep them alive? Should they be fertilized?

A. Pulling these plants out with a pickup truck and chains would have drastically damaged the cambium layer which can reduce the flow of water and other nutrients through the plant. They were also kept out of the ground for a week before being replanted. These plants could pull through if they are tough, but you will need to make sure they are kept moderately watered. Don’t overwater, but don’t allow the plants to dry out either. A slow trickle for about 10 minutes a couple of times per week will help to rebuild the roots. Do not fertilize them. Fertilizing a stressed plant can further stress the plant. Only time will tell if they can survive.

7. This caller has lilacs that are looking bad and didn’t bloom well. What can be done to help them? When can they be pruned?

A. Sounds like this lilac is in need of a rejuvenation pruning. This is where you cut the plant off about 6-8 inches above the ground level to rejuvenate the growth. It will reduce insect problems and push new, young growth to provide better blooming and have a healthier plant. This can be done in the fall for best results.

8. A caller had bagworms on her cedars last year. She also noticed a lot of praying mantis egg cases, she knows they are a good predator.  Are the praying mantis’ helping to control the bagworms?

A. Praying mantis’ are not a major predator of bagworms. They prefer feeding on aphids and others.

She also wondered about her forsythia that was injured by the late frost this year. It didn’t bloom this year and she had to cut back some of the branches. Will it bloom next year now or did this damage the blooms for next year as well?

A. The blossoms are set on the new growth that will form this summer. As long as they are pruned back within about 3 weeks after their bloom period, they will still bloom next year. This is why we prune forsythia just after they bloom rather than in the late winter. This forsythia should still bloom next year.

She had one final question, how can she control a clover-type weed growing profusely in her iris beds?

A. This will be difficult to do without harming the iris plants. She could spray with Roundup using a piece of cardboard as a barrier between the weeds and the iris plants or she could use the “glove of death”. This is when you wear a chemical-resistant glove and then put a cloth glove over that. Then, dip a few fingers of the gloved hand into Glyphosate and rub those fingers along the stem and leaves of the bindweed to kill it.

9. What can be done to control elm saplings in a windbreak?

A. You can go through and cut off the trees and follow that up with a stump treatment using either 2,4-D or a glyphosate product, such as Roundup. The Roundup would be better this late into the year to avoid volatilization issues from the 2,4-D in the heat. Use the concentrate and just paint it on to the freshly cut stump for best control. Do NOT use Tordon, that will likely kill the spruce trees, and it is against label directions.

10. A caller planted grass in the spring. It is getting to about 2 inches tall now. When can he spray the weeds coming in with the grass?

A. You should wait until after 3 times mowing the new lawn before any herbicides should be applied to the grass to avoid injury. However, by that time, it will be too hot to use any 2,4-D products, which will turn into a gas and move to non-target plants and injure them in temperatures above 80-85 degrees. It would be better to just wait it out and spray in the fall to manage the weeds after the turf is more established. The fall is a better time to treat for perennial broadleaf weeds because it is when the plant is taking nutrients back into the root system and it will take more of the herbicide with it. Spray twice in the fall, once in mid-September and again in early to mid-October.

11. This caller has a hydrangea that didn’t look like it was going to live through the late frosts this spring. She did notice that it is finally coming up but it is only about 3 inches tall and is setting blossoms on. Should she remove those or let the plant bloom at such a small size?

A. It would be best to remove those blooms to allow the plant to grow a bit more before trying to bloom. All the energy in that plant would push into flower production, at such a small size, it would be best to allow the plant to build leaves and the root system to help it so it comes back next year.

12. A caller wants to know what to do to keep iris blooms from falling over?

A. Sometimes if the flower is too heavy it can fall over a bit. There are metal rings you can purchase to put in flower beds around plants that fall over to keep them upright, but nothing else will work for this. The flower is just too heavy for the stalk.

13. If branches on a tree or shrub are already dead can they be pruned off now?

A. Yes, dead branches should be removed as soon as they are noticed to prevent injury or damage from a falling branch.

14. The final call of the show asked if they should be fertilizing lilacs that were planted 3 years ago?

A. Fertlilizer doesn’t need to be used on plants that are growing just fine. Most trees and shrubs can get the nutrients they need to survive from our soils. The best thing is to do a soil test prior to adding any soil amendments, nutrients can build up to a too high level which can also damage the plant.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

Yard & Garden: May 8, 2020

This is the Q&A for the Yard and Garden show for May 8, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the show has shrubs that bloomed this spring, when can they be pruned?

A. Any shrub that blooms in the spring should be pruned within about 3 weeks following the spring bloom period. This would include plants like lilac, forsythia, and the spring blooming spireas.

2. A caller heard me discussing the need to cover tender annuals for the next few nights with the cold temperatures predicted. Do those need to be uncovered during the day or can the cover just stay on for the next few days? Does she need to cover her wisteria or strawberries that are just beginning to bloom?

A. The plants that should be covered are annuals and tender perennials, this includes the warm season crops that have already been planted in your garden this year. You can cover them with a sheet, a row cover, or a bucket. They should only be covered at night. In the morning, when the temperatures warm up above 40 degrees, the coverings should be removed to allow the plants to receive sunlight. Perennials, including wisteria, should be fine. Strawberries that have blossoms set would push new flowers and fruit later but if you don’t want to lose this first crop, you may put a row cover or sheet over the plants to protect the developing fruits.

3. This caller has a flowering tree that is suckering in the lawn. How can they control the suckers without harming the tree?

A. If these are growing in the yard, they can just be mowed over and will eventually die but not harm the tree. You can also cut the suckers off individually, if desired. Don’t treat these with any herbicides like roundup because it can go into the main tree and kill that as well. While some products, such as Sucker Stop are available, these will only slow sucker growth; not stop it. Some trees and shrubs are more prone to suckering. For example, crabapples, purple leafed plums and lilac.

4. A caller has 3 acres of bare area to manage. What is the best or cheapest options for him regarding grass or some other type of covering?

A. Native grass or pollinator or wildlife mixes would be a great option for this type of location. You can purchase seed at many locations including Anderson Seed from Odell or Stock Seed Farms from Murdock.

5. This caller has black spots on her grass that have recently showed up. She wasn’t sure the type of grass but most likely it was Kentucky bluegrass.

A. It is hard to tell for sure what the problem is from the description given. I asked for a photo to be emailed to know for sure.

cedar-apple rust gall
Cedar-apple rust gall on Cedar Tree

6. A caller has cedars that have developed odd orange structures on the branches. What is that and how can it be controlled?

A. These are the galls of cedar-apple rust. This disease needs 2 hosts to complete its lifecycle. The galls are hard, gray/brown structures on the cedar trees over the winter. In the spring, when it rains, these galls open up to allow the spores to move to the apple trees. When the galls open up they are orange structures that resemble an octopus due to all the telial horns around the gall. The disease causes no problems to the cedar trees, but will cause lesions on the leaves and fruits of apple trees. If you have a susceptible apple tree, now is the time to spray with a fungicide to prevent the disease from affecting your tree. For more information, view this NebGuide.

7. This caller has asparagus growing. This is the 4th or 5th year of growth. He has fertilized often but not this spring. He did use a weed and feed on the asparagus, but asparagus wasn’t listed on the label. Why is his asparagus growing so spindly?

A. As we harvest, eventually the spears will start to get spindly which means that is the time to quit harvesting for the year. However, the weed and feed product may have some negative consequences on this plant. He didn’t know what exactly the product was that he used but he said it didn’t have asparagus listed on the label. In this case, the product should NOT be used on the asparagus. Make sure to always read and follow the label on pesticides and only use it on plants listed on the label.

8. A caller has planted potatoes a couple of different times this year, but they continue to not sprout. What would be the problem?

A. The weather has been fairly cool, and especially cold overnight. The plants are just waiting for more desirable weather before growing. Give them a little more time and they should grow as long as a disease doesn’t set in or they rot in the ground.

9. If volunteer redbuds have come up throughout a landscape, can they still be moved to a more desired location this year or is it too late?

A. Yes, they can still be moved now. As long as they are moved prior to the hot, dry environment of late June through July and August, they should be fine.

10. What is the best way to manage weeds around asparagus?

A. Mulch is the best option to keep weeds down around asparagus. You can use the preen that has asparagus listed on the label to control annual weeds. Otherwise hand-pulling will help keep them down as well. At the last harvest of the season cut down all the spears, so there’s no foliage or anything above the ground. Rake the soil over the top of the spears. Then spray the plants with glyphosate (RoundUp). Glyphosate becomes bound by the soil particles when it hits them, so will not damage the crowns below ground. This will control annuals and tough perennial weeds. The spears will then re-emerge from the soil and not be damaged by the glyphosate at all. Apply some mulch to help with the weed control, then Preen.

11. This caller gets little brown spots on the leaves of her cucumber plants every year. This often will kill her plants over time. Is there anything she can do to control this so her plants will survive longer?

A. Using mulch and watering at the base of the plants with soaker hoses will help. Overhead irrigation, such as with sprinklers, can splash disease spores from the soil to the leaves of our plants or from leaf to leaf or plant to plant. Watering from below helps reduce the spores splashing. Mulch also helps to keep the separation from the soil where the spores are. Fungicides, such as a copper fungicide, could also be used if desired. Make sure that cucumbers are listed on the product and follow the PHI (Pre-Harvest Interval) for length of days to wait from application to harvest.

12. A caller has spiny vines growing up the trees in her windbreak. How can she kill the vines and not harm the trees?

A. You can go through and cut off the vines and follow that up with a stump treatment using either 2,4-D or a glyphosate product, such as Roundup. Use the concentrate and just paint it on to the freshly cut stump for best control. Do NOT use Tordon, that will likely kill the spruce trees, and it is against label directions. When cutting the vines off at the base, they will stay in the tree but they will die because they have no roots. Treating the base of the plants will kill the roots to eliminate the problem with regrowth.

13. This caller has a patch of asparagus is not doing well this year. He recently piled logs nearby the patch. Would those logs be causing a problem with the growth of the asparagus? The logs are about 3 feet from the asparagus.

A. The logs shouldn’t be causing a problem from that distance, there isn’t black walnut in the wood piled there. It may just be that the asparagus needs to be fertilized. A general fertilizer can be applied in the spring to help with growth. If the spears are getting spindly now, harvesting should be discontinued. The plant will tell you when to quit harvesting based on the size of spears.

14. A caller has cucumbers, zucchini, and potatoes that have just emerged their first leaves. Should those be covered this weekend with the cold weather that is predicted? Would peonies need to be covered?

A. Yes, those warm season crops that have very tender new growth should be covered for the next few evenings. Remember to uncover them during the day. The peonies should be fine, but a freeze could damage the developing flower buds depending on how cold it gets, how long it stays that cold, and how far developed the buds are.

15. This caller asked how to spray her apple trees to prevent problems with insect and disease problems.

A. Orchard fruit tree sprays will combat both insect and disease problems on fruit trees. Sprays should begin as soon as pink is seen in the buds, but should cease during blooming. Since this caller hasn’t begun spraying yet, it would be fine to just start as the blossoms are falling off the tree. You want to allow the pollinators to come to the tree without harming them, so no sprays should be done while the trees are blooming. This spray should be applied every 10-14 days through the growing season, up until harvest.

16. The final caller of the show has a concolor fir that the needles on the bottom third of the tree have turned brown. What is causing this problem?

A. It was hard to determine the problem with this fir over the air. I asked for follow-up photos to help diagnose the problem.

 

Yard & Garden: May 1, 2020

This is the Q&A for the Yard and Garden show for May 1, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the day has a plant that comes up in his grass, he calls it onion weed. They have tried 2,4-D products but it is still alive and keeps coming back and spreading. What is it and how can it be controlled?

A. This is likely wild garlic or wild onion due to the onion/garlic smell of the leaves when you break them. They are very difficult to control in the lawn. Multiple application of post-emergence herbicides such as Roundup or 2,4-D products. If using the roundup you will need to reseed the area as roundup will kill all plants, including the turf. You can also dig them up as you see the patches appear. It is best to mow just prior to spraying but not mow for a couple of weeks after spraying.

2. This caller has something that is boring holes in his yard. There are a bunch of holes in the yard that are 1 inch in diameter with very fine soil around the holes. What would cause this?

A. There are a few options for this. He wasn’t sure how deep the holes went but didn’t see any runs in the lawn around the holes. Without a few images of the damage it is too difficult to give a definitive answer.

3. Is it too late to start spraying peach trees for insect and disease damage?

A. To have a peach tree on a spray schedule with an Orchard Home Fruit Tree spray, it is best to start when the buds begin to open up and show pink behind the sepals. Then, you would spray every 10-14 days through the growing season except during the bloom period. This will help with insects and diseases. If you didn’t get started before the bloom, you can start now that the tree has finished blooming.

4. A caller has hostas that have grown very large and thick. Can they be divided?

A. Yes, now would be a good time to dig them up and divide them. They can be divided in half, thirds, or quarters depending on the size of the plant. After they have been divided, replant them, make sure to space them out correctly. Keep them well-watered once replanted because they will have a limited root system.

5. This caller is curious about catchweed bedstraw and what to do about it.

A. This weed is found throughout our landscapes. It is a winter annual weed like henbit. It can be pulled very easily because it has a very shallow root system. You can also spray it with a 2,4-D product or Roundup.

6. A caller is wanting to plant tulips in his landscape under a tree. Would this be a good location for them and do you need a lot to get good coverage under the tree?

A. Yes, tulips will grow well under trees but you do have to plant a lot to get a good effect from them. They should be planted in the fall, such as early October.

7. What can be done about moles in the yard?

A. Trapping can be used on moles. It is most effective using a Harpoon type trap and if you prepare the area prior to setting the trap. Find an active run by stomping it down a few times before setting the trap. If the run continues to pop back up, set the trap there the third or fourth time you stomp the run down. This should ensure get the mole. For more information view this NebGuide.

8. This caller has 2,4-D that froze in the container. How can he get rid of that?

A. If you can find a pesticide disposal location, that would be best. However, if you cannot find one, the best way to dispose of pesticide is to apply it to a labeled site (specific plant, animal, or structure) for which the product is registered. Always double check the product label to be certain that the site is listed and that the maximum application rate will not be exceeded.

9. The final caller of the day wanted to know how to get pampass grass to spread. Can it be pruned a certain way to encourage spreading?

A. No, you can’t prune it any way to encourage spreading, it will just take time. Over time it will grow larger to fill an area better or you can divide the plants to spread them out farther, but nothing else will be effective for spreading.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

Yard & Garden: April 24, 2020

This is the Q&A for the Yard and Garden show for April 24, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller of the day had his yard sprayed for broadleaf weeds yesterday. How long should he wait before overseeding the lawn?

A. According to the label of Trimec, grass cannot be reseeded until 3-4 weeks after applications from the product. Any 2,4-D product would be similar. At this point, it would be best to wait until the fall to overseed the lawn, because that late in the spring would be hard to get the turf established. Be sure to tell your lawn company not to spray it in the fall until after the new grass has been mowed 3 times in the fall.

2. Can you start sweet potatoes from the sprouting sweet potatoes purchased from the grocery store?

A. You can, but they may not grow quite as well as desired. The varieties in the grocery store may not be as hardy as some of the varieties from the garden centers.

3. This caller is planting cucumbers, zucchini, pumpkins and other cucurbit plants. How far apart do they need to be planted to prevent cross-pollination?

A. The cross-pollination affects the produce in the following year, not the current growth period. The produce on the plants this year will be fine, but if they cross-pollinate, the fruits produced next year may not be true to the variety you are saving seed from. They also have to be in the same species to cross-pollinate, and cucumbers and zucchini are not.

4. A caller has rhubarb plants that are producing seed heads. Why is that happening so early and should anything be done about that?

A. The cold temperatures from last week are unusual and have “confused” the plants. This has pushed the plants to produce seed stalks. When rhubarb plants begin to produce seed stalks they push their energy into seed production and not into leaf and stalk production. To push that energy back into the stalk production we desire from rhubarb, cut the seed stalks off of the plant.

5. This caller has a rose garden that has chives coming up among the roses. What can be done to manage the chives and not harm the roses?

A. Among other plants it is best to use the “glove of death” which is when you wear a chemical-resistant glove and then put a cloth glove over that. Then, dip a few fingers of the gloved hand into Glyphosate and rub those fingers along the leaves of the chives to kill it. This will likely take multiple applications over multiple years to completely rid the garden of the chives, but this is best to not harm the roses.

6. A caller is wondering what the best method is for transplanting 5 foot tall peach trees?

A. The best time for this would be in the dormant period, either in the fall or late winter months. Be sure to get as much of the rootball as possible.

7. This caller has planted the Hairy Balls plant and now grass is growing up among the plants. Can Grass-B-Gon be used in these plants to kill the grass and not harm the plants?

A. It should be fine, Hairy Balls plant is in the milkweed family which is not a grass. It would be best to avoid spraying directly on the foliage of the desired plant to ensure limited exposure.

8. This caller started lettuce, spinach, and some herbs before the snow. They have not come up yet. Will they be ok or should they be replanted?

A. Give the plants a little more time to see if they come up yet. If they hadn’t germinated yet, they should be ok, but the soil temperatures were too cold with the snow and freezing temperatures last week for them to germinate. If they don’t come up soon, you can try to reseed or move these crops to a fall garden because we are going to start getting too warm soon.

He also wanted to know if his strawberries will survive? He planted them as roots prior to the snow, and they had no real above-ground growth prior to the snow.

A. Those should be fine, because they hadn’t started to grow yet. The roots should have been protected enough to survive.

9. A caller has strawberries that are growing in a raised bed. The strawberries in the center of the bed seem to have died out. Can she move some new starts from the outside edge to the middle now? Also, what should they be fertilized with? She has some 11-15-11 can she use that?

A. Yes, it is ok to move established plants now to fill in the bed better. The fertilizer she has would be fine to use. Just be sure to follow the label instructions on applications.

10. When can a magnolia tree be pruned to allow a lawnmower underneath?

A. The timing for tree pruning has shifted a little recently due to new research. The International Society of Arboriculture has moved the time frame to correspond with the spring growth flush which would be May through early June for southeast Nebraska. This allows the tree to seal up the wound faster with less disease and insect issues.

11. This caller has snowball bush hydrangea plants that are spreading and growing into the lawn. Can he divide the plants to move the plants that are spreading into undesired areas to grow in better locations?

A. Yes, either do it now or in the fall. When you dig them up, they may be attached to the main plant, just prune that connection off to move them.

12. A caller has iris plants that had pushed new leaf growth and then were hit by the snow and the tips of the leaves are brown and discolored. What should be done with that?

A. The plants will be fine. It might be best to wait until a few more leaves appear that are not brown, then the entire leaf that is brown can be removed. Wait to get more new leaves to avoid removing all the sugar producing leaves to be removed now.

13. What are some good plants for pollinators? Where should these be purchased?

A. Good choices would include butterfly bush, butterfly milkweed, milkweed, goldenrod, coneflowers, bee balm, sunflowers, coreopsis, and many more. They can be purchased at local nurseries and garden centers. Pollinator seed mixes can be found at some seed supply companies, including Stock Seed Farms in Murdock, NE.

14. The final caller of the day planted pampass grass it started to green up, but now after the snow nothing seems to be alive. Will these plants be ok?

A. Give the plants a couple more weeks to see if they will regrow. The roots should still be fine and it is likely that they will regrow, but if nothing in a couple of weeks, there would still be time to replant these.

*Reference to commercial products or trade names does not imply endorsement by Nebraska Extension or bias against those not mentioned.

Yard & Garden: April 10, 2020

This is the Q&A for the Yard and Garden show for April 10, 2020. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 31, 2020. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: No guest host due to COVID-19 and social distancing

1. The first caller asked when the best time is to transplant peonies?

A. The best time is in the fall. They can be done in the spring though, as well. You may want to mark the depth that they are planted at currently to ensure they get planted at the same depth at the new location. Use some masking tape or some other way to mark their depth now. If peonies are planted too deep, they will not flower.

2. A caller has Austrian pines that started turning brown last year. He was told to spray them with a copper fungicide in the spring, is that correct?

A. This sounds like dothistroma needle blight which is common on Austrian Pines and Ponderosa Pines. This disease will cause the tree to turn brown, typically from the bottom up with brown bands on the needles upon closer inspection. Needle blight is best controlled with 2 applications of copper fungicide, one in mid-May when the new needles have emerged to about half their size and a second application in mid to late June.

He also asked if he can plant asparagus now?

A. Yes, asparagus is a spring plant. It can be planted in April or May. Asparagus should be planted in a trench 6-8 inches deep. The recommendation has always been to cover the crowns with 2 inches of soil at first and wait until they emerge to continue to add 2 inches of soil each time until the soil level is even with the surrounding soil. However, research shows that this isn’t necessary. The asparagus should still be planted in a trench 6-8 inches deep, but it can be completely covered back up right away to still be successful.

3. Is there any herbicide that can be used to control weeds in a pumpkin patch?

A. Unfortunately, the majority of these herbicides for use in pumpkins are restricted use and can only be purchased and used by individuals with a pesticide applicator license. For a general backyard pumpkin patch, mulch will be your best option to manage the weeds before they become established. Hand pulling through the season will help as well.

4. This caller had planted spinach and radish a few weeks ago. They had emerged and then were covered with snow and ice last week. Now the tops have burned off entirely. Will they regrow?

A. Unfortunately, if the entire tops of these plants were killed with no green showing, they will not likely regrow. You can wait a week or so to see if they regrow, but it may be time to replant these crops. If they were small they don’t have very much for reserves left in the roots to get new growth back.

He also has asparagus growing but it is continually very spindly. What can be done about that?

A. When asparagus is small and spindly, it may need some fertilizer to help it grow thicker, larger stalks. A general garden fertilizer can be used now, in the spring or a manure or other type of fertilizer can be used in the fall.

5. A caller has a 7 year old peach tree and very old apricot trees that are in full bloom right now. With the freezing temperatures predicted for the next several days, will they produce fruit this year?

A. It is not likely that they will survive these freezing temperatures at the stage they are at. Temperatures are predicted to be in the low 20’s for several nights starting on Sunday. According to research by MSU, apricots in full bloom will have 10% blossom kill at 27 degrees and 90% blossom kill at 22 degrees. Peaches in full bloom will have 10% blossom kill at 27 degrees and 90% blossom kill at 24 degrees. If we can stay a little warmer, at that 27 degree mark you should still see a good fruit set this year, but if we do get the cold temperatures predicted it is not likely to have much of a crop. To see more scenarios and more fruits, visit the Spring Freeze Damage Thresholds Guide.

6. This caller had broccoli growing in her garden. The foliage was burned by frost, but she had planted the plants in a tin can with the bottom cut out placed in the soil and placed a bucket over the plants during the cold nights. Will the plants survive?

A. There is still green in the stems, so they should come back. Give the plants a week or so to determine if new leaves emerge. If they don’t put on new leaves in the next week, it is likely that they won’t survive and need to be replanted. Broccoli can take temperatures down to 26-31 degrees, so they should have been ok. You will want to make sure that the plants are covered again, overnight, for the next few days while more cold temperatures are predicted. The predicted temperatures are lower than what the broccoli can survive under normal growing conditions.

7. Is it too late to plant peas? Can tomatoes be planted now?

A. The peas are ok to be planted now, but it might be a good idea to wait until after this next week when the temperatures are to get very cold overnight. Peas can only take temperatures down to 31 degrees. Tomatoes are a warm season crop and shouldn’t be planted until the beginning of May. If planted in a wall-of-water or other protective method, they can be planted in late April. I wouldn’t push the plants too much earlier than that because they don’t survive cold temperatures and won’t grow.

8. A caller has a blue spruce tree that is losing the needles on the east, southeast side of the tree. This area that is dying is not on the shady side of the tree. The trees are about 20 years old.

A. This caller sent photos to me after the show. After further discussion, it was determined that the tree could possibly have a few issues that are common on blue spruces. I assume they may have had some spidermites last summer that killed off a lot of the needles as well as needle cast disease. The spidermites can be sprayed off with a strong spray of water that will knock them off and kill them. There are miticides labeled for use on spidermites, but sometimes using pesticides can kill the predatory insects as well for spidermites causing more of an outbreak. The needle cast disease can be treated by spraying chlorothalonil or copper fungicide on the trees. Fungicide applications should be made in May when the new needles are 1/2 to 2 inches in length and every 3-4 weeks as rains continue. For more information on needle cast, view this publication from the Nebraska Forest Service.

9. Should marigolds be planted into containers or directly into the ground for best growth?

A. Either will work just fine. Marigolds will make a good container garden plant or they can be used among your perennials and other annuals in gardens in the ground.

10. This caller wants to know how to keep grass out of the asparagus? When should preen be used if that is an option?

A. Preen will work well on asparagus. Make sure you use the preen that is labeled for use in asparagus. It can be applied anytime in the early spring on established plants. When dealing with newly planted asparagus it would be best to wait until the asparagus has begun emerging from the ground. Mulch will also help with weed management in asparagus. Grass clippings, straw, or wood chip mulch can be used on asparagus. If applied early enough, the mulch can be a very effective weed control.

11. Can preen be used on flower beds?

A. Preen would be fine in flower beds, as long as the flowers in the garden are listed on the label of that Preen product. However, if any of the flowers are annuals coming up from seed or perennials that are allowed to grow through seed dispersal in that garden, the preen will stop the germination of those coming up from seed. Do not use it in areas where you plan to grow via seed.

12. A listener wondered about relocating lilacs. Can it be done, if so when?

A. Yes, they can be transplanted. The fall would be the best time for this.

13. The last caller of the day has some hickory and pecan trees to plant. Can they be planted around a black walnut tree?

A. Yes, hickory and pecan trees are in the same family as black walnut and therefore are not negatively affected by the juglone that the black walnut produces to reduce weeds around it.

He also wondered if a pawpaw tree can be planted around other trees?

A. Yes, pawpaw is best grown as an understory tree with partial shade.

Yard and Garden: June 14, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for June 14, 2019. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 2, 2019. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Dr. Paul Read, Professor of Viticulture, UNL

1. The first question of the show was what to do to get rid of borer bumble bees that are burrowing into the framing of a shed?

A. These are carpenter bees. Carpenter bees are a good pollinator insect. If they aren’t damaging the structure of a building, they can be left alone. However, if they are digging into framing for a shed or other building, filling the holes in with wood putty should work. Otherwise, you can spray a little sevin in the holes as well. You might also try putting up a Bee Hotel that may be more desirable to them than the structure of your building. View this article on Carpenter Bees for more information. View this NebGuide on Creating a Solitary Bee Hotel to learn how to build and place a bee hotel on your property.

He also wants to know what likes peas? His plants bloomed and then something ate the top third of the plant off. What would do that?

A. This could be deer, rabbits, or squirrels. These are all difficult wildlife to control. Fencing 2 feet high around them will keep rabbits out, the fencing needs to be 4 feet tall to keep deer out. Squirrels can climb the fence, so they are more difficult to manage in the garden. For more information on controlling squirrel damage, view this NebGuide on squirrels.

2. A caller has 4 peach trees, 2 have been producing fruit while 2 have not. Are there male and female peach trees? When will the other 2 produce?

A. Peaches are not male/female trees, they have perfect flowers and are self-pollinating. If they aren’t flowering they are not mature yet. Once they begin flowering they will produce fruit.

3. Are cedars asexual trees?

A. Cedars are dioecious, meaning that they have male and female flowers on separate trees. You can see the difference in the trees in the spring when one tree looks brown while the next tree is green.

4. This caller has roses with holes in the leaves. What is causing this?

A. This is due to rose slugs, which is the immature form of a sawfly. Rose slugs are not terribly damaging. They can cause some defoliation early in the summer months but only for a few weeks and the damage is minimal. Spraying for rose slugs could harm pollinators while the plants are blooming.

Roseslug Collage
The picture on the left shows the rose slug on the underside of the leaf. The picture on the right shows the damage from rose slugs.

5. A caller just planted some gooseberry bushes. What care should be given to them now? Do they need to be cut back annually?

A. Gooseberries require minimal care. Cut out any damaged canes each year, but otherwise, leave them alone.

6. This caller was wondering about a plant called ‘Thuja’. Will it grow ok here?

A. Yes, Thuja is the genus for arborvitae. Arborvitae will grow fine here, but it can be problematic in cold snap winter conditions. They get a lot of winterkill. A local nursery will have varieties that are better suited to our environment than those found in a mail-order catalog.

7. A caller has an American Elm that is dying. Last summer it lost all of it’s leaves early, now the tree looks dead on portions. What is wrong with it?

A. This could be from Dutch Elm Disease. There are still elms in the area that have made it through Dutch Elm Disease, but the disease will catch up with them and kill them. There is no cure or anything you can do to save a tree from Dutch Elm Disease. Remove the tree.

8. This caller has a 14 year old maple tree with branches hanging on the ground making it difficult to mow around. Can those branches be cut back now?

A. Yes, it would be fine to prune it back now. This time of year is beneficial because the wound will seal up quickly with the active growth of the tree. Be sure to make a good pruning cut. For tips on how to make a good pruning cut, view this article from Sarah Browning on Pruning Deciduous Trees.

9. A caller has a rose bush that bloomed good for a while, now it has started to die. The leaves and flowers are wilting. She waters 1 inch per day. What is wrong with them?

A. Watering the plants 1 inch of water a day would be excessive. It would be better to reduce that down to 1 inch of water per day, especially with all of the rain we have been seeing lately. Be sure to add a 2-3 inch layer of mulch to the plants. Don’t fertilize them right now, fertilizing a stressed plant can further stress it.

10. This caller is looking for a source for corn gluten meal for weed control.

A. Try looking at local nurseries like Campbell’s or Earl May. Be careful with corn gluten meal, if too much is applied it can kill desirable plants.

11. A caller is using rural water now instead of rural water that they had used before moving. The rural water smells like bleach, will it hurt the plants? Also, she adds manure every year to it, is the soil causing problems to the plants?

A. The water shouldn’t affect the plants. If there is a concern, you can get the water tested to ensure that it is safe for consumption. Also, be careful just adding manure every year. It would be a good idea to get the soil tested prior to just adding more nutrients. Nutrient levels that are a little high can be just as detrimental as low nutrient levels.

12. The last caller of the day started his tomato plants in the upside down planter. Should he put a cage around them?

A. That wouldn’t be necessary because the plants are going to naturally grow upward. Cages are used on the ground to keep our plants from falling over, these would be held up by the planter.

Battling Weeds in the Lawn

5-4-11 (2)

September is a time for the lawn. In my last article, I discussed overseeding and fertilizing the lawn, but weed control is another key to a healthy lawn. Some weeds in the lawn are often tolerated, but when the weed population begins to outweigh the turf population, management should be incorporated.

The Battle with Weeds

Plants are considered weeds because they are adaptive, aggressive and opportunistic. Weeds come into a lawn that is thin or bare. They are often found on the edges of our lawn or places where the grass doesn’t grow as well. Eventually they will work their way into the rest of our lawn. So overseeding a lawn may be the answer to reducing the weed population.

Growing turfgrass in the shade is not always possible. Even the shade mixes are not made to grow in high shade. Dense shade is not the growing condition for turfgrass and it often leads to weeds. In some cases, trees may be pruned to improve the sunlight getting to the turf, but be careful not to ruin the shape or health of a tree or shrub  just to get more sunlight to the turf. If the shade is too dense, a good alternative might be a shade tolerant groundcover or apply mulch where grass won’t grow.

Crabgrass

Crabgrass has been found in high populations this year, even in locations where crabgrass preventer was used. The University of Nebraska-Lincoln Turf department says the weather is to blame. Crabgrass germinates when soil temperatures reach 57-64 degrees at a one-inch depth, with the highest germination when soil temperatures increase to 73 degrees. Crabgrass will continue to germinate through the summer until soil temperatures reach 95 degrees. With the unusual weather we had this spring and summer, the largest amount of crabgrass germinated later than normal when the concentration of our original spring crabgrass pre-emergence herbicide was declining. This is why we saw so much more crabgrass later this summer than we usually do.

To help prevent this problem with later emerging crabgrass in the future, switch to longer lasting chemicals, such as prodiamine. You can also look to a second application of crabgrass preventer in mid-June to stop the germination of the late flush of crabgrass. There are also post-emergent herbicides to use for crabgrass, but I don’t recommend them this late in the season. Remember, crabgrass you are seeing now will die when the first frost hits. Also, it is difficult to kill a large crabgrass plant with a post-emergent herbicide.

Broadleaf Weed Control

As for when to treat for broadleaf weeds that do come into our lawns, fall is the best time to control them. In fall, perennial weeds are moving carbohydrates from the leaves into the roots for winter storage to help get them going again next spring. If you spray them in the fall, the herbicide will also be moved into the roots which makes the herbicide more effective. Also, the weather is more suitable for herbicide use than in the spring when Dicamba and 2,4-D have a potential to drift to non-target plants. Fall is also a great time to apply herbicides to kill the winter annual weeds such as Henbit either with a pre-emergent herbicide such as prodiamine (Barricade) or dithiopyr (Dimension) or with a post emergent after the henbit has germinated.

2018-04-20 12.52.00
Henbit along a sidewalk edge

The best time to apply herbicides in the fall is mid-late September and again in mid-late October. The second application helps to get better control on perennial weeds that may have been missed or were not fully killed. The second application also helps to ensure that winter annuals have germinated to help get control of those with a post-emergent herbicide. Products containing 2,4-D, carfentrazone, sulfentrazone, quinclorac, or triclopyr are all good for controlling perennial weeds in the lawn. Use caution around trees, shrubs, and landscape beds as these products can damage broadleaf plants but they will not harm our turf.

Yard and Garden: April 14, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for April 14, 2017. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through July 28, 2017. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: George Pinkerton, Director of Landscape Maintenance at Downtown Lincoln

1. The first question came from a caller wondering what the timing is for crabgrass preventer?

A: Typically we go with mid-to late April for application of crabgrass preventer. Crabgrass germinates when soil temperatures reach 55-60 degrees Fahrenheit. In most of the Southeast Nebraska area, we have just recently hit that. Anytime in the next couple of weeks would be fine to apply your crabgrass preventer. It might be best for control to apply a split application this year. For a split application, apply half of the recommended rate now and the other half of the recommended rate 8-10 weeks later. The split application will give you a longer season of control for crabgrass and other annual grassy weeds.

2. A caller was wondering about their gladiolus bulbs. They have had problems with thrips insects in the past and they had heard they should soak their bulbs in lysol to control them. Is this a good method of control or is there something better?

A: As it turns out, you can soak the corms in a solution of lysol water prior to storage of the corms over the winter months, according to the University of Minnesota Extension. You can also dust the corms with a sevin dust prior to storage in the late fall, store them with mothballs, or store them at colder temperatures such as 35-40 degrees F as well. If you are looking for control at this time, it would be best to spray the plants as you see the streaking damage beginning from the thrips feeding in the spring and summer months. You can use any general insecticide for this.

3. This caller has a sugar maple that was hit with hail 5 years ago and now has a great deal of damage to the trunk of the tree. They have sprayed the trunk with a sealant and used a wrap. Will the tree survive or should it be removed now?

A: At this point, I would observe the tree to watch for signs of death occurring through the tree. The damage that is there cannot be fixed now that it has occurred. If you don’t like the look of the damage you can remove and replace the tree or you can wait until it starts to dieback. It is hard to say how long the tree will live now that the damage has occurred.

2012-05-25 12.04.38
Bare lawn in need of overseeding.

4. A caller wants to reseed. What seed should he use?

A: For a new seeding, use a turf-type tall fescue or a Kentucky bluegrass. Use either 100% of either of these types or use a 50% mix of the two. For more information, see this article from the UNL Turfgrass Department on Choosing Grass Seed.

5. A caller has a section in fairly high shade that died out last year. Why and can it be reseeded?

A: In locations of very high shade turf doesn’t always do well. The caller said this had been growing there for 25 years so it could have been a fluke that the lawn died out last year. You can reseed now with regular turf or you can use a shady groundcover such as a carex species.

6. When is the time to transplant coreopsis to a location with more sun?

A: Now would be a great time. Mid April through mid-late May is a great time to transplant perennials.

7. This caller has some large pin oaks that need to be pruned to make it easier to mow underneath the tree. Is it too late now to do that?

A: Yes, it would be better to wait until late fall to prune the oaks now. Oak trees are susceptible to oak wilt which is spread by a beetle in the summer months. It is best to avoid pruning them at this time of the year to reduce the incidence of disease.

8. What kind of tree would be a good choice for shade production in a backyard?

A: Any of the oak species, shagbark hickory, sycamore, Linden, Kentucky coffeetree, Black locust, thornless honeylocust, hackberry, and many others.

Curly Dock, Steve Dewey, Utah State Univ, Bugwood
Photo of Curly Dock from Steve Dewey, Utah State University, Bugwood.org

9. A caller wants to know what to do for management of curly dock?

A: 2,4-D or Trimec can be used this time of year or use a mixture of 2,4-D and Roundup.

10. What do you do for thistles growing throughout a yard?

A: 2,4-D or Trimec, but these products are best used in the late fall or before flowering. Thistles are a biennial so if you can dig up the plants as a rosette in the first year of growth they will die.

11. This caller has cherry trees that are suckering. Can one of the suckers be dug up now to start another plant?

A: Yes, it can be done now, but fall would be a better time of the year for this. If it needs to be done, it can be done now. However, depending on the type of sucker growth, the new plants may not be the same as the original plant or they may have weak growth.

12. An email from a listener asked what is wrong with his pin oak that has leaves that are curled up like they were hit with a spray? He wondered if they were too close to the windbreak that is 20 feet away? Is there a certain distance you want to stay away from your windbreak when planting other trees?

A: You do need to give your trees space to grow, but pin oaks are often planted as a third, interior row to a windbreak. The spacing between rows would be 15-20 feet, so the proximity to the windbreak would not be a problem in this instance. Most of the time if a tree is lightly hit with spray drift from a pesticide, it will not show in the tree every year unless it is hit every year. In this case, I would ask for a picture or sample to help with further diagnosis.

13. When is the best time to transplant peonies? Why isn’t the rhubarb up yet?

A: Fall is the best time to transplant peonies. If necessary for construction or moving purposes, it can be done yet this spring. Plant them at the same depth at their new location. As for the rhubarb, give it a few more weeks to see if it comes up before giving up on it. If it is in a location that is more exposed to cold winds the soil may have not warmed up enough yet this spring.

14. This caller wants to know what type of fertilizer to use in a garden?

A: A low grade, balanced fertilizer is best for a garden, like a 10-10-10 or 12-12-12 with slow release fertilizer is best.

15. The final caller of the day wanted to know if now was the time to fertilize pecans?

A: Many of the trees in our environment have sufficient nutrients for growth and so fertilization on these pecan trees may not be necessary. If you are concerned with the growth of the tree, take a soil test to see where the fertility levels are. If it is growing fine, don’t fertilize it because our trees and other plants can be over-fertilized which can cause injury or even death.

Yard and Garden: May 27, 2016

Yard & Garden for blog

This is the Q&A for the Yard and Garden show for May 27, 2016. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 5, 2016. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Dick Campbell, Owner of Campbell’s Nursery in Lincoln

1. The first question of the day came via email. A listener wanted to know how to control clover in their lawn?

A. Clover is best managed in the fall months when it is pulling nutrients from the leaves into the roots, it will take the chemical into the roots as well. Products with triclopyr work best, but 2,4-D will work as well. Make 2-3 applications in September and October for best control.

Mallow, Phil Westra, Co State Univ, Bugwood
Common Mallow photo by Phil Westra, Colorado State University, Bugwood.org

2. A walk-in question was for identification of a weed.

A. This weed is mallow. It is a difficult weed that will move throughout our gardens. It can be controlled with a careful application of Glyphosate (Roundup). Be careful not to spray any other plants with the glyphosate product.

3. A caller wanted to know when she can transplant daylilies and Iris?

A. The daylily could be transplanted now. It would be best to move these in the spring or in the fall, but daylilies are a tough plant and would be fine if moved now as long as they are kept well watered when it is hot because the root system isn’t developed at the new location yet. Iris would be best if transplanted in the fall.

4. A caller has earthworms making his lawn uneven. What can be done to control those?  This caller also wanted to know if he can water houseplants with water that goes through a water softener?

A. Earthworms are very beneficial to our soils as they reduce compaction and add organic matter back to our soils. The damage from them is only seen for a couple of weeks in the spring with rains. If you can deal with it for a short time, it is best to avoid treating for them. If you have to treat, Sevin insecticide does have some management capabilities for your lawn. As for watering the houseplants with water from a water softener, it is best to use water prior to the softener due to the increase of salts in the water.

5. This caller wants to know how far away from the house a shade plant should be planted? She also wants to know how she can manage grass in Iris’?

A. Spacing the tree from the house depends on the tree chosen and what the full size of that tree is. For many of the oak or maple shade trees, it is best to go 25-35 feet or farther from the house to ensure no problems develop as the tree grows. The grass in the Iris bed can be controlled with Grass-B-Gon.

6. A caller has a cherry tree that the top broke off but it is still attached to the main trunk. Can it be saved?

A. There is no way to re-attach a broken off branch. This branch will have to be removed. Because this is the only branch that is still producing leaves and cherries, the tree should be removed and replaced.

7. A caller has 2 rhubarb patches that were damaged badly by hail. The leaves look terrible. Should those leaves be removed or left on the plant?

A. If there are new leaves growing below the damaged leaves, the damaged leaves can be removed. However, if those damaged leaves are all that is alive on the plant right now, they should be left on the plant until new leaves begin to grow so that the plant can still grow and build nutrients for next spring.

8. A sample was brought in of a trumpet vine with many little insect all over the stem, leaves, and flowers. The plant has been sprayed with Sevin with no control. What can be done for this trumpet vine?

A. Sevin is not an effective method of control for aphids. In high populations you can use Eight or Malathion. Aphids are not very damaging to our plants and they are fairly short lived. Given time, predatory insects will move onto the aphids to control them without chemicals.

9. This caller was looking into planting apple trees and found there is a disease called cedar-apple rust. Is this a concerning disease here and what should be done to avoid problems with it?

A. Yes, cedar-apple rust is a damaging problem for apple trees. The spores can spread up to 2 miles, so it is best to plant a resistant apple tree cultivar. It is also good to look for cultivars that are resistant to apple scab. For choosing your cultivar, here is a publication from Purdue that lists common apple tree varieties and their disease susceptibility: Disease Susceptibility of Common Apple Cultivars

10. A sample was brought in of a tulip tree with leaves that are puckered and rolled downward. What would be the problem with this tree?

A. This tree has aphids on the underside of the leaves that are sucking the juices out of the leaves. Aphids are not terribly damaging to our plants and are fairly short lived. In high populations you can use Eight or Malathion.

11. Is there a dry granular weed killer for the lawn? When is the time to move gooseberries, iris, peonies, and rhubarb?

A. Fertilome is a good dry, granular weed killer. This is best applied early in the morning so it will stick to the leaf blades with the morning dew. Gooseberries should be moved after dormancy. Iris and peonies should be moved in the fall, typically in September when the tops begin to turn yellow. The rhubarb should be moved after they are dormant in the fall or early spring.

12. This caller has asparagus that has been planted in this location for many years and is now dying out. She fertilizes 2-3 times per year with a general fertilizer. What is causing this problem and can it be fixed? She also wants to know if she can use canning salt or Epsom salt in her garden? And, finally, she wants to know what to do for the aphids on her honeysuckle?

A. Asparagus will die out due to age. It would be beneficial to dig it up this fall after it goes dormant and divide the plants to replant as individual clumps. When replanting, sprinkle some bone meal in the hole to help with fertility. As for using epsom salt in the garden, this is not necessary. Epsom salt is magnesium sulfate which is in good supply in Nebraska soils. If nutrients are necessary in your garden, it is best to use a general purpose fertilizer. Canning salt can harm your plants and damage the soil. It is not a recommended practice to use any type of salt in your garden. As for the honeysuckle aphids, those should be controlled with Eight or Malathion. The aphids on honeysuckle can cause witches broom to the plant so they should be controlled.

13. Do raspberries and blackberries need to be grown on a trellis?

A. Yes, a trellis or an espalier would be a good way to grow them. Here is a good guide to growing raspberries and blackberries from Missouri Extension

14. Can red and black raspberries be planted together?

A. Don’t plant them within 20 feet of each other or they will cross pollinate and the fruits will not taste as good.

15. A caller has rhubarb that is shooting up stalks with seeds on them. What should be done with those?

A. Those seed stalks should be removed. Cut the stalk off at the ground. If left the plant will put energy into producing seed that should be stored for leaf and stalk production.

16. The last caller of the day has a mandevilla plant that is growing outdoors in a pot with a trellis. The leaves are now turning yellow and black. What is causing this and how can it be managed?

A. This is a moisture issue. The heavy rains this year are causing a leaf fungus to occur. A rose and flower systemic containing a fungicide can be applied to the plant to help reduce the disease.

Yard and Garden: May 20, 2016

Yard & Garden for blog

This is the Q&A for the Yard and Garden show for May 20, 2016. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 5, 2016. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Natalia Bjorklund, Dodge County Extension Educator

1. The first caller of the day has a problem getting grass to grow where he removed an asparagus patch. What can he do to get his grass to grow?

A. This is a situation where it could be a few things attributing to the problem. He was keeping the seedbed watered, by watering it 3 times a day for about 10 minutes each time he watered. Watering is important for seedlings, they need to be kept moist, so short, frequent waterings are necessary. This area could be compacted from years of asparagus growth, so it might be beneficial to till the area up prior to planting. The other issue he is facing this year is that it has been quite cool this spring. Mixing the cool temperatures with the moisture, it might be too cold for germination. It is suggested to try again with new seed after tilling the soil up and a soil test may be necessary after that to ensure the soil is ok after so many years with asparagus on it.

2. A caller has a newly planted red maple tree with holes in the leaves. They do have black spots on the leaves as well. The new growth seems to not be affected like the original leaves. What would be the problem? Is this an insect issue?

A. This could be a leaf spot fungus with black spots on the leaves that have died out. When a leaf spot occurs on tree leaves, often the dead area will fall out of the leaf. Leaf spots are not very damaging to our plants. Since the new growth seems ok, it shouldn’t be treated and the tree will grow out of it and be fine.

3. A gentleman has evergreen trees that have brown tips on the branches. Is this being seen in other locations?

A. This is probably just an environmental problem on the branches that should fade in time. It is being seen in other trees, especially in white pines which are facing problems with winterkill, a common issue where the tips of needles on white pines turn brown after strong winter winds. It is not a concerning issue.

4. This caller wants to know how to control weeds growing around her containers that she is growing tomatoes and strawberries in? Can any chemicals be used that close to these crops?

A. Tomato plants are especially sensitive to chemical drift especially from 2,4-D which is a common herbicide used for lawn weeds. To be safest and not have problems from the 2,4-D being that close to the tomatoes and strawberries, mechanical control would be the safest option. mulching around the containers will help to keep the weeds from coming back.

5. A caller has blackberry leaves that are turning orange and then back to green. What would be causing this?

A. This sounds like the plant is having an issue with rust. The rust covered leaves then are falling off and new, uninfected leaves, are reappearing. Remove all infected leaves as soon as you notice the fungal spores. Rust will not kill the plant, it may show up on the berries slightly. Chemical controls are not necessary for a home gardener.

6. A gentleman planted fescue grass seed this spring and it seems to be a thin stand. Should it be overseeded? Will it fill in?

A. Fescue does not tiller out like bluegrass does. So it should be overseeded to help fill in the gaps in the turf.

7. What chemical can you use for tree stumps to help keep them from growing back?

A. 2,4-D is a good option to apply to a newly cut stump or drill into the stump and pour it into the holes. It can be mixed with Roundup to help as well. Do not use Tordon in a landscape setting as this would be a direct violation of the law.

8. This caller transplanted peonies a few years ago and they haven’t bloomed since they were moved. What is wrong with them?

A. If peonies are planted or transplanted too deeply in the soil they will not bloom. Dig the plants up and reposition them higher in the soil profile. It can be done now or in the fall, the fall would be the preferred time of the year.

2015-06-25 10.19.56
*Reference to commercial products or trade names is made with the understanding that no discrimination is intended of those not mentioned and no endorsement by University of Nebraska–Lincoln Extension is implied for those mentioned.

9. An email listener wanted to know if fertilizer changes composition over time?

A. Yes, it can break down and become less effective. If fertilizers are stored where they freeze and thaw continually or get moisture into them, they will not work as well as they originally did.

10. A caller has a windbreak that is dying. What are some good tree choices to replace the windbreak with?

A. Cedars, black hills spruce, Colorado blue spruce, Douglas fir, concolor fir, white pine, ponderosa pine, or Jack pine would all be good replacements. Make your windbreak out of a diverse selection of these trees. Don’t go with a windbreak of one tree species.

11. This caller has a peace lily that the leaves turn brown and then die back. It continues to go through this process. It has been repotted but is still exhibiting the damage. What is it and how can it be improved?

A. This could be due to overfertilization or too much salt content in the water. Try using distilled water for a while. It will flush out the salt content from previous water over time. Eliminate the use of any fertilization. It is a common problem in peace lily plants and they should be fine.

12. What chemicals can be used for bagworms and when should they be sprayed?

A. Bagworms are typically active in the third week of June and this would be the best time for spraying. The emergence of the bagworms is weather dependent and it can range from the middle of May to late July. Average years it is the third week of June for the timing of sprays. It is best to just watch your tree and spray when the new bags are 1/2-1 inch in length. You can treat them with general insecticides such as Sevin, Eight, Bt, or Tempo.

fern leaf peony, Lee Ruk Flickr
Photo of fern leaf peony from Lee Ruk via Flickr Creative Commons License

13. The last caller of the day wants to find a fern leaf peony. It seems to be hard to find. Where could she find this plant to purchase?

A. It should be fairly easy to find at a local nursery. Many of the box stores probably will not have this unique and interesting plant.