Yard and Garden: July 19, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for July 19, 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: Jay Seaton, District Forester for the Lower Platte South NRD

blossom end rot zucchini
Blossom end rot on a developing zucchini

1. The first question of the show was regarding fruit development on zucchini. The fruits begin to develop and then one end begins to die. What is causing this?

A. This sounds like blossom end rot, it can happen in zucchini, tomatoes, peppers, watermelons, and others. Blossom end rot is when the end of your vegetable that is away from the plant rots and turns black. It occurs on the end of the vegetable that had the flower, hence the name blossom end rot. The cause of this disease is a calcium deficiency, but calcium is in the soil in sufficient quantity, uneven watering will reduce the ability of the plant to access this calcium. Calcium has to be dissolved in water for the plant to be able to obtain it from the soil. Adding calcium to your garden is not effective for managing this problem. Not all of your produce should be affected by this problem, they tend to grow out of these conditions later in the summer, so there is no need to treat your garden for blossom end rot. Maintain moisture and mulch to help with this disorder.

This caller also wondered why his pole beans are not producing yet. He shared the seed with a friend and that friend has harvested but he has not. Why is that?

A. This is likely an environmental issue. Give the plant a little more time to produce the beans. The friend’s garden would have a different microclimate from your garden it may have more sunlight or more heat radiating from a nearby building that your garden doesn’t have.

2. This caller has zucchini that is dying. They seem to have rotten roots when going to look at why they have died. She waters with a hose on trickle twice a week for 30 minutes each time. What is wrong with them?

A. This sounds like too much water is getting applied to the plants. Jay estimated that this was likely applying about 5 gallons of water per week, which is quite excessive. It would be better to use a soaker hose or measure the amount of water applied to the plants each time you let the hose trickle. Vegetable gardens only need about 1 inch of water per week.

3. A caller has pickling cucumbers that are growing good but as they grow one end of the cucumber becomes smaller than the other end. What would cause this?

A. This is likely due to heat stress. There isn’t much we can do to avoid damage from the hot weather. Make sure that the plants are mulched and they are receiving the correct amount of water.

4. This caller has tomato plants with brown leaves at the bottom of the plant. What is causing this?

A. This is likely a fungus. We have seen quite a bit of early blight this year already. Look for concentric rings in the brown spots on the leaves. If it is just a few leaves, pull those leaves off the plant and destroy them. Be sure to keep the plants mulched and water from the base of the plant rather than overhead irrigation to help reduce the spread of the disease.

japanese beetle JAK582
Japanese Beetle, Image from Jim Kalisch, Retired from UNL Entomology

5. What can be done about Japanese beetles? This caller said she was going to try traps and wondered about homemade traps.

A. Don’t use traps, they will attract more Japanese beetles than what you have in your landscape already. Spray all of the areas at the same time. She said one day she would spray the garden, the next a shrub, and the next a tree. If you avoid spraying in areas where they are commonly found, those other locations will become a safe haven for the beetles. Sevin is a good insecticide to use to control the beetles. Be sure to read and follow the label for spraying every 10-14 days and for the PHI, to know when it is safe to harvest again after spraying. Using grub control in the lawn can help. You can also go out in the evening when the beetles are grouped up to knock them into a bucket of soapy water to kill them.

6. This caller wants to know if they should hold back on fertilization of roses and garden now due to the heat?

A. If your plants look fine, don’t worry about fertilizing them right now. Avoid fertilizing the vegetable garden this time of the year. If the nitrogen level is too high around vegetable plants, the plants will grow large and beautiful but will not produce fruit because nitrogen is for leafy growth of the plant. I usually advise avoiding fertilization of the garden this late in the season.

7. The last caller of the day has a sweet potato vine with holes in the leaves. She saw a grasshopper the other day, would that be causing the problem?

A. This could be from grasshoppers, especially since you saw some on the plant. Use Sevin to treat for them. Make sure you spray the grassy ditches and roadsides as well, which is where grasshoppers are found more often.

She also has zucchini plants that have gray, translucent spots on the leaves. What would cause that?

A. She sent a picture to clarify the problem. It looked like a slight fungal disease. It is nothing that is too damaging to the plants. Copper fungicide could be used but I don’t think it is necessary. Good sanitation is key to controlling fungal diseases in the garden. Mulch the garden and avoid overhead irrigation during the season to help prevent splashing spores from the ground and from plant to plant. Remove the plants from the garden at the end of the season.

Yard and Garden: July 12, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for July 12, 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: Sarah Browning, Extension Educator in Lancaster County

1. The first question of the show was about ivy growing on a garage. The caller had Japanese beetles earlier this year and sprayed with sevin. Now he is seeing a lot of flying insects, one looks like a lightning bug. What type of insect would this be and will they cause damage to his ivy?

A. They could be lightning bugs which will not harm your plants. Japanese beetles will come back, it would be best to keep spraying to ensure they stay away. You can use the sevin every 10-14 days or you can use a product containing Azadirachtin which has some repellent properties so it will help to keep the Japanese Beetles away longer.

2. A caller has a newly planted maple tree that has brown spots on the leaves. It looks like something is eating it but she can’t find any bugs. The spots look like brown strips with yellow around it. What is causing that?

A. This could be the tree drying up and getting heat stress. This tree was just planted this year so it isn’t established well and will dry out faster in this heat. She has been watering by hand and that isn’t getting the tree enough water. It would be better if she watered with a small sprinkler for about 45 minutes once a week.

3. This caller has a 40-year-old Ponderosa Pine that had diplodia tip blight that got so bad she removed the tree. There is a blue spruce nearby, would that tree be getting the tip blight as well? The spruce has tips of the branches that are bent over and the needles are all bunched together. What would cause that?

A. Diplodia tip blight will not affect spruces. It is a problem for pines, mostly Austrian and Ponderosa. This is not what is affecting the spruce. The damage on the spruce sounds like sirococcus shoot blight. It is past the treatment time for this disease, but it won’t kill your tree in one season. In the spring spruces can be sprayed with chlorothalonil when the shoots are 1/2-2 inches in length and repeated every 3-4 weeks if frequent rains occur.

Blossom end rot on tomato
Blossom end rot on a tomato

4. What can be done for blossom end rot in tomatoes?

A.  Blossom end rot is when the end of your vegetable that is away from the plant rots and turns black. It occurs on the end of the vegetable that had the flower, hence the name blossom end rot. The cause of this disease is a calcium deficiency, but calcium is in the soil in sufficient quantity, uneven watering will reduce the ability of the plant to access this calcium. Calcium has to be dissolved in water for the plant to be able to obtain it from the soil. Adding calcium to your garden is not effective for managing this problem. Not all of your produce should be affected by this problem, they tend to grow out of these conditions later in the summer, so there is no need to treat your garden for blossom end rot. Maintain moisture and mulch to help with this disorder.

5. A caller wants to know what to plant for a fall garden and when it should be planted.

A. Fall gardens can be very beneficial and work better than spring gardens due to the cooler temperatures and higher amounts of moisture in the fall. Start transplants indoors now for things like Brussels sprouts, broccoli, cabbage, and cauliflower. The average first frost date for most of Southeast Nebraska is October 6-16, this comes from data from the High Plains Regional Climate Center. You can use the first frost date to figure out when to plant fall crops. Use the first frost date as a starting point, count backward the number of days to harvest listed on the packet of seeds and add a 10 day fall factor because the plants will mature slower due to the cooler weather. Plants or seeds should be planted in late July to early August. You can also plant your second crop of warm season vegetables now if you haven’t yet to get a longer harvest period and possibly avoid problems with insects and diseases during their peak time.

6. This caller has a rose bush with something eating the leaves off it. What would cause this and how can it be controlled?

A. This could be from a couple of different issues. Japanese beetles will feed on the leaves of roses and cause the leaf to look like lace with little leaf left besides the veins. Rose slugs can do some damage to roses but it looks worse than it is and the feeding should be nearing completion for the year. If you aren’t seeing the insects, it could be rose chafers that feed at night. It could also be from a disease such as black spot. Look for a product that contains an insecticide and fungicide to help with any of these problems. A liquid would be better than a dust.

7. A caller has brown spots in his lawn. What is the problem and how can he fix it?

A. This could be due to either brown spot or dollar spot. These two diseases are quite common this year due to the wet spring and early summer conditions we faced. In a home lawn it isn’t usually necessary to use a fungicides because the fungi don’t kill the lawn and they are sporadic from year to year. It will fade soon and the grass will green back up. These diseases don’t affect the crown of the grass plant so it will easily grow out of it after a few mowings. Through discussion, we learned that his underground sprinkler system waters the lawn from 1am-6am. It was suggested that he do an irrigation audit and move the time for watering forward to 4am-10am. Watering overnight keeps the lawn wet in the cooler, dark environment which is great for disease development.

8. The final caller of the show have sugar maples that leafed out well this year but now the leaves are turning brown and dropping off the tree. What is causing that?

A. This could be from anthracnose, a fungal disease of the tree. It can infect the leaves and cause them to fall from the tree. It could also be from not watering enough now that the rains have reduced or from scorch. Be sure to water the tree and look for damage on the trunk or girdling roots. Look for borer holes as well and treat with imidacloprid if holes are present. It is most likely from an environmental condition, which we cannot change. The tree should be fine.

Yard and Garden: July 27, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for July 27, 2018. 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 3, 2018. 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: Steve Karloff, District Forester for the Nebraska Forest Service

1. The first caller of the day has tomatoes that are rotten on the bottom. What is wrong with them and what can be done?

A. This is blossom end rot, it is where the blossom end (or the end of the tomato farthest from the plant) rots. It is due to a calcium deficiency due to uneven watering. The calcium is in the soil, but uneven watering makes it unavailable to the plant. Mulch will help keep the soil at a uniform moisture level to help protect plants from this disorder. Blossom end rot is a short-term problem in our vegetable crops. It tends to only affect the plant for a the first couple of harvests of the year and then the plant grows out of it. You can cut the black end off of the fruit and eat the rest.

2. When is the best time to prune lilacs? This caller has one that is a large, overgrown lilac that needs to be pruned.

A. The best time to prune a lilac is in the spring within a couple of weeks after blooming has concluded for the season. If it is a very large, old plant, it can be pruned all the way back to 6-8 inches above ground in a rejuvenation pruning. Rejuvenation pruning does just what the name says, rejuvenates an old, less productive plant to provide better foliage, flowering, and overall health. Rejuvenation pruning can be done in the fall. The lilac will not flower for a couple of years following this type of pruning, but it will bloom again.

3. This caller planted a large amount of black walnuts last year. Now the weeds are taking over the trees. How can the weeds be controlled without injuring the trees?

A. Simazine is a pre-emergent herbicide that can be used around walnut trees that have been established for at least 12 months. This is a pre-emergent herbicide so it won’t clean up the weeds that are growing now. For those weeds, it would be best to do hand weeding with a hoe to not injure the roots of the trees and then apply the Simazine this fall. Be sure to follow the label on how to apply and how to mix the chemical.

4. A caller has a redbud tree that is 15 feet tall and is now developing a split where multiple leaders have forked up from the main trunk. What can be done to prevent further splitting? Can one side of the tree be removed to fix the split?

A. The best option would be to remove one side of the tree or bolt it together. However, removal of one side of the split would result in removing too much of the canopy of the tree. Either side of the split would be pruning off a branch that is more than 1/2 the size of the trunk, which is not recommended. Because this is a redbud, and it shouldn’t get much larger than it is now, bolting the 2 sides together may be an effective management option for this tree. A bolt in a larger tree in this situation would likely not be very effective once the tree grew to full size, but with a smaller tree it would be more beneficial. The best thing for all trees is to remember to prune them while they are young to prevent these situations from occurring, but that is not always an option and it is hard to remember to do this.

5. This caller has some pin oaks that were planted 2 years ago and are 2-4 feet tall. The new leaves are being eaten off the tree. The leaf veins are still on the tree, but most of the rest of the leaf is gone. He has looked and can’t seem to find any caterpillars. What would cause this and how can it be managed?

A. This is likely due to scarlet oak sawfly. It is a common pest of oak trees that has 2 generations per season here and we are just finishing up the second generation in the immature stage. Because the damage is mostly finished for the year and because the tree faced minimal damage, there is no need to spray for this sawfly.

6. A caller had a daylily plant that she transplanted a month ago and it died. What caused that? What time of year is best to transplant peonies?

A. June and July are not the time of year to transplant anything, it is too hot, humid and dry to move a plant. I would assume the daylily died due to heat stress. When a plant is moved, it takes time to build the roots back up to where they can survive such heat and low water that we see in the summer months. It is best to wait to tranplant anything until the spring or fall of the year so they can become established in cooler temperatures than in the heat. Peonies can be transplanted this fall, in September. Remember to keep the plant at the same depth in the soil or it will not bloom.

7. The last caller of the day sent some photos of his red maple trees wanting to know if they will survive?

A. The trees were planted last year and now one of them has no leaves on the top 1/2 of the canopy of the tree. The other has very wilted leaves. When the top half of a tree dies like this, it is likely due to a watering or root issue. I would say this tree should be replaced, it will not grow out of it. The roots could have been injured in the nursery or at the garden center he purchased the trees at. The roots also could have been injured when they were planted. The tree that is still fully leafed out may have a chance to live, give it TLC and it might pull through. Water the tree with 1 inch of water per week and add a mulch ring around the tree that is 2-3 inches deep. The leaves could be wilted due to heat and drought stress and the watering and mulch will help it to survive.

Yard and Garden: July 13, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for July 13, 2018. 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 3, 2018. 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: Bob Henrickson, Horticulture Program Coordinator for the Nebraska Statewide Arboretum

1. The first caller of the day has a bug zapper that was recently emptied. The zapper contained quite a few of these small, brown, bean seed-shaped insects. What would this insect be?

A. Based on this description, it could be June bugs. These smaller, copper colored beetles are common right now and they are attracted to lights at night. If you have a lot of June bugs, you may want to pay close attention to your lawn and any possible brown spots in it. The immature stage of June bugs are white grubs that feed on the roots of our turf.

2. A caller has a climbing rose that is 8-10 years old and it was recently cut down to about 15 inches tall, against the homeowners wishes. Will this plant survive?

A. This isn’t the ideal time to prune a rose, but it should be fine since prior to the pruning it was in very good condition. Make sure to keep the rose well-watered and keep a layer of mulch around it to keep it healthy during this time of heat as the rose will try to push new growth. Water it with 1 inch of water per week unless natural rainfall provides that. Keep the mulch 2-3 inches deep.

3. This caller has an elm tree that has a hole in the base of the tree that goes in about 1 foot deep. Will the tree be ok?

A. A picture was requested for this tree to determine the severity of the hole. This could be due to many different factors including a crown rot, root rot, or other type of root damage. The hole is not very large, but because it is a foot deep, there is a concern for the strength and stability of the tree. Keep an eye on the hole, if it gets larger or if the canopy starts to thin, it would be a concern that would need to be removed before it falls on something.

blossom end rot, tomato, David B. Langston, Univ of GA, Bugwood
Blossom End Rot on Tomatoes, Photo from David B. Langston, University of Georgia, Bugwood.org

4. A caller has a black spot on the bottom of his tomatoes. What is causing this and can it be cured?

A. This is blossom end rot, it is where the blossom end (or the end of the tomato farthest from the plant) rots. It is due to a calcium deficiency due to uneven watering. The calcium is in the soil, but uneven watering makes it unavailable to the plant. Mulch will help keep the soil at a uniform moisture level to help protect plants from this disorder. Blossom end rot is a short-term problem in our vegetable crops. It tends to only affect the plant for a the first couple of harvests of the year and then the plant grows out of it. You can cut the black end off of the fruit and eat the rest.

5. This caller has a tropical hibiscus that she has moved outdoors for the summer. This hibiscus was looking fine but now some of the leaves are turning yellow. She waters every other day and it is on a wood patio on the south side of her home. What is causing this yellow color?

A. This could be heat stress due to the fact that this plant is in a location on the south side that gets very hot. She also should test the soil with her finger prior to watering to be sure to not overwater. If the soil is dry, water. If the soil is still wet, wait longer before watering again. This could also be due to spidermites. You can test for spidermites by placing a sheet of white paper below a few of the leaves and tapping on the leaves. If a few pieces of pepper seem to be moving on the paper, that is spidermites. If it is spidermites, the plant can be sprayed with a strong spray of water to knock the mites off and kill them or you can use Eight (permethrin) on it.

6. A walk-in listener brought in a plant that he needs identified. It is growing like a shrub with orange and red berries and it is spreading rapidly. What is it?

A. This is a plant called Tatarian Honeysuckle, it is a weedy species. It is spread rapidly by birds. Cut it off now before it becomes more established. Treat the stumps with Roundup or Brush Killer.

Sandbur, Rebekah D. Wallace, Univ of GA, Bugwood
Sandbur, Photo from Rebekah D. Wallace, University of Georgia, Bugwood.org

7. Does 2,4-D work on sandburs?

A. No, sandburs are a summer annual grass like crabgrass. Using a pre-emergent herbicide in the spring for crabgrass will control sandburs as well. If you didn’t use a pre-emergent in the spring, Roundup would work on sandburs but 2,4-D will not be very effective.

8. This caller has chokeberries that are about 4-5 years old and starting to set on. How do you know know when they are mature for harvesting?

A. At this point of the year, there should be clusters of small green fruits setting on the shrubs. The berries will turn dark purple in color when they are mature. There is a large harvesting window for chokeberries and the birds don’t come to this plant until after clearing the berries off of more preferred plant species.

9. A caller has sunflowers that were planted from seed and they have been coming back. The plants are similar to other sunflower plants seen around town but the flowers are much smaller than neighbors’ flowers. Are there different types of sunflowers?

A. There are a lot of different varieties that would influence the size of the flowers. Sunflowers are annual plants, so if they are coming back each year, they are coming back from seed. Sunflowers may not be true to seed so the type of flower may have changed over time or from year to year.

puncturevine seeds, Steve Hurst, USDA NRCS PLANTS Database, Bugwood
Puncturevine seeds, Photo from Steve Hurst, USDA NRCS PLANTS Database, Bugwood.org

10. This caller wondered if the caller from question #7 may have been referring to puncturevine as they are commonly confused?

A. These plants do commonly get confused because they both produce a seedhead that sticks to your clothes or shoes. They are both annual plants as well. However, puncturevine is a broadleaf while the sandburs are grasses. A 2,4-D product will work to control puncturevine, but the pre-bloom stage is going to be most effective.

11. The final call of the day has bugs flying around their tomato plants and eating the tops of the fruits. What is that?

A. After seeing a photo of the damage to the fruits, it was determined that this is due to the tomato fruitworm. Tomato fruitworms can be controlled with sevin or eight. If there are insects flying around the plants as well, that is likely something different such as Japanese beetles. It is possible, and likely, that this caller has multiple insect issues. However, both of these pests will be controlled if he sprays for one, they are both affected by the same pesticides.

Yard and Garden: May 11, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for May 11, 2018. 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 3, 2018. 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 caller of the show has asparagus beetles. How can they be controlled?

A. Use a dust or spray formulation of Sevin to control the beetles. When using chemicals around vegetable or fruit crops, be sure to pay attention to the PHI listed on the chemical label. The PHI is the Pre-Harvest Interval which indicates how much time must pass between the application and harvest to avoid pesticide residues. You can also hand remove the insects, destroy them in a bucket of soapy water after removal. The asparagus beetle should be controlled because they will lay their eggs on the asparagus as it grows which can reduce the saleability. Also, their feeding can reduce the amount of ferns produced which can weaken the plant.

2. A caller has a Bing cherry tree that has been planted in the landscape for a few years and it is not growing and seems to be dying. What is wrong?

A. Sweet cherries, including Bing Cherries, do not grow well in Nebraska weather. For cherries in Nebraska, tart cherries will grow here and do best.

3. This caller has grapes that are not taking off that are in their second year of growth since planting. He has 2 varieties, but not sure which varieties they are. What should be done to get them growing better?

A. Grapes are self-pollinated, so only one variety is necessary. It would really depend on what varieties this caller is growing to know for sure what is wrong with them. They may not be the best choices of varieties for this area. For a listing of good varieties to choose from, visit the UNL Viticulture Program website. For good general care: the plants should be trellised and will be productive by the 3rd year. Water is very important for establishment in the first year. It would be beneficial to mound the soil around the base of the plant during the winter to work as insulation.

He also wanted to know if he could move strawberries into an old baby pool? Would this be enough space for the plants to grow?

A. They would be best grown in the ground, but could live in a baby pool as long as there are drainage holes in the bottom of the pool so the soil doesn’t get saturated.

blossom end rot zucchini
Blossom End Rot on Zucchini

4. How do you deal with blossom end rot in vegetable gardens?

A. Blossom end rot is due to uneven watering. It is technically a calcium deficiency, but the calcium is there it’s just not available to the plant due to the water issues. Even watering is going to be key, it is just hard to do in Nebraska when we face drought periods in between heavy rains. It is just best to water the plants 1 inch of water per week over the week to ensure even, adequate watering. Typically, when we see blossom end rot, we only see it for a couple of weeks early in the season, it is not usually a season-long condition.

5. A caller wants to control the dandelions in her lawn and also reseed. How can she do this safely?

A. We are really ending the window of opportunity for reseeding a lawn this year. It is difficult to get turf established when temperatures start to rise in May. Dandelions are best controlled in the fall with a broadleaf herbicide. At this point, the timing for both control of the dandelions and overseeding the lawn would be around the same time. However, you should not overseed the lawn and use herbicides at the same time or the herbicides could injure the turf seedlings. Tenacity, or a product containing Mesotrione can be used at seeding to control broadleaf weeds and not injure the grass seedlings. I would advise using this tactic in the fall or to overseed in late August to mid-September and allow the grass to grow enough to be mowed 3 times and then use a late fall application of a 2,4-D product to kill the dandelions. If there is time for a second application of the 2,4-D at least 2 weeks after the first application and into the early part of November, that would be most beneficial.

6. This caller has plum trees and elm trees growing in their peonies. What can be used to stop the regrowth of these weedy trees without harming the peonies?

A. The safest option would be to cut the trees off then paint glyphosate (Roundup) on the cut stumps shortly after pruning. Be careful to not get the glyphosate on the peonies to avoid damage to them. I would advise against using 2,4-D in this situation to avoid volatization of 2,4-D and causing problems to the peonies.

This caller also wanted to know if she can use Grass-B-Gon products in the peonies and iris’ to control grasses growing in the plants?

A. Yes, this is labeled for use in broadleaf plants to kill grasses.

7. A caller wants to know what she can use for weeds in the asparagus patch?

A. mulch is going to be the best option for any type of weeds in asparagus. Our herbicides are not labeled for use in this vegetable crop. After she is done harvesting the asparagus for the year, she can cut it back so all green growth is below ground and glyphosate (Roundup) can be used over the bed. This could be used in the fall after the season, followed by mulching the plants in to reduce new growth.

8. This caller has a disease on his pine trees. Is it too late to spray the trees to prevent the disease?

A. This is likely either needle blight or tip blight. The timing for spraying for needle blight is in mid May as the needles are emerging, with a second application in mid to late June, so it would be the correct time to spray for this disease. If the disease is the tip blight, the timing for spraying for that is in the third week of April, just before the needles emerge with a second application 7-14 days later. You would be past the prime window for this disease, but it would still be beneficial this early to treat for this disease as well to avoid too much spread of the disease. With the spring as cool as it has been this year, most things are pushed back a bit and fungicides would still be beneficial for these trees.

9. A caller asked why tordon could not be used for the weedy trees in the peonies that caller #6 asked about?

A. Tordon will kill the peonies as well. Tordon is a mobile chemical that can get from the roots of these trees and into the roots of the peonies, killing them as well. Also, Tordon is not labeled for use in a landscape setting, it is only labeled for roadsides and ditches.

10. This caller has 2 viburnums that are growing in her yard. One has leafed out fine but the other leafed out only part of the way and has now stopped emerging from winter dormancy. Will it be ok?

A. Don’t give up on the plants too soon this year. The spring has been quite cold and unusual for our plants. The general recommendation is to wait until June 1st before determining death in the plants. Because it started growing, it is likely that it will be fine. Make sure that the plant is getting plenty of water to help it pull through. If the plant begins to sucker from the base, this could be a sign that the top had cold damage.

11. A caller has 2 ornamental grasses that haven’t greened up yet. Will they survive or are they dead?

A. Just like with the viburnums, give the plants time to come out of their winter dormancy. Many of the ornamental grasses have not begun to green up this year yet. Wait until June 1st before deciding to destroy the plants that may just be slow to come out of dormancy this year.

12. This caller’s lawn is brown and pulls up with no roots attached. Could it be grubs?

A. If there are no roots attached to the grass, it is most likely due to grubs. Grubs can be managed with a grub control product applied to the grass in mid-June. For the grass that died, you can overseed the area in late August to early September.

13. A caller has a patch of rhubarb that is not growing much and is going to seed early. What can be done about that?

A. Rhubarb will start sending out seed-stalks in warmer weather. Some varieties, though, are more prone to send out seedheads early in the season. Cut off the seedheads as you see them start to form to push energy back into the roots and leaf production rather than into seed production for the plants.

This caller also wanted to know if you can root lilacs from a cut branch?

Lilacs are difficult to get to root. The best chances to get it to grow would be to take a piece from the base of the plants that has roots attached to it already. Divide the plant by taking a section off the side of the plant would be best.

14. What would be a good choice for an organic weed killer for dandelions?

A. If the population is manageable, hand removal would be the best organic choice. There are other products such as corn gluten meal and dried distillers grains which are used for pre-emergence weed control. According to the University of Minnesota, ‘It should be noted that any claimed herbicidal effects of Dried Distillers Grains have not been proven or verified as they have been for corn gluten meal’. For post-emergent organic weed control, vinegar can be used, but it is non-selective so it needs to be used as a spot spray. It is important to remember, that bees love dandelions and a small population can be tolerated and helpful for our pollinators.

15. The final caller of the day wants to know about mulching her garden. She uses straw but wheat comes with the straw mulch. What can she do?

A. Straw mulch can bring weed seeds with it, but it does make a great mulch for a vegetable garden. It would be best to shake the straw out over a tarp before applying it to the garden to pull most seeds out of it. Also, using older straw would help so that the seeds would have all germinated before use. Grass clippings make another great garden mulch. Just make sure that the grass was not treated with a pesticide before applying it to the garden. The pesticide label will tell you if or when those grass clippings can be used on a garden again this year. Grass clippings do break down quickly, so it is best to reapply this mulch often or the weeds will poke through.

Yard and Garden: July 8, 2016

Yard & Garden for blog

This is the Q&A for the Yard and Garden show for July 8, 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: Dr. Paul Read, Viticulture Specialist for Nebraska Extension with Guest Intern Vivian from China

If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/9b24 and be entered to win a free plant book or some free UNL gifts.

1. The first caller of the day wanted to know if they can prune the Cleveland Pear tree that has branches that are low and too tight to the trunk?

A. The best time for pruning a tree like this would be while it is dormant. For a situation like this where the caller is only removing a few branches to help with the growth of the branches and to reduce future problems with the tight branch arrangement it would be fine to remove them now. It would be better to remove branches like this before they break in a storm due to weak attachment to the trunk.

2. A caller has Anjou pear trees that were planted in 2013. Now the bark from the graft union up about 10-12 inches has the bark peeling and now has some black leaves. What would cause this?

A. This would be from sunscald. There is no way to fix sunscald once it occurs. Don’t paint the wound with anything, allow it to heal itself. The black leaves could be due to fireblight. You can cut 6-8 inches past the diseased portion of the limb to cut the fireblight off the tree. The black could also be anthracnose which is not damaging to the plant and there is no need to spray anything for anthracnose.

sunscald-bugwood
Sunscald Photo by William Jacobi, Colorado State University, Bugwood.org

3. This caller has an oak tree that is dripping sap on the vehicles parked under it. What would cause this?

A. Aphids feeding on the leaves of trees will excrete honeydew that can drip on vehicles underneath the tree. Aphids are not very damaging and have a lot of predatory insects that feed on them. They can be sprayed with sevin or eight or another general insecticide, but they should fade out on their own with predator insects.

4. A caller has blue spruce trees that look dirty but the tips are still green. What would cause this?

A. This is most likely due to environmental stress from the heat and humidity. If the ends of the branches are still green, the tree will be fine. Make sure your tree has a mulch ring around it and that you keep it well watered in the heat of the summer.

5. This caller has a patch of lilies where a quarter of the patch has only grown to be about 6 inches tall for the past 2 years. The rest of the patch looks good, but this area doesn’t look healthy. Can these be improved?

A. This could be due to hardiness in some varieties that are only suitable for our environment for a couple of years. It also could be due to some bulb mites. It would be a good idea to dig up some of the bulbs to see if they have any damage on the bulbs.

6. A caller has a pine tree with a lot of sap on the branches and the grass in the lawn won’t green up. Why is this?

A. Woodpeckers or insects feeding on a pine tree can cause sap to leak from the wounds left behind. The insects can be controlled with bifenthrin or permethrin (eight). If it is woodpeckers, the damage is minimal and will not cause any problems to the tree. Check how much water the lawn is actually receiving by using catch cans during the water intervals normally followed. Lawns need 1 1/2 inches of water per week. If the water is fine, there are a lot of fungal diseases in the lawn, it could be one of those. Fungal diseases in the home lawn are usually sporadic and therefore don’t require fungicide applications.

7. This caller lives on an acreage surrounded by farmground. She is considering growing grapes on this large plot of land. Are grapes easy to grow and would grapes have a benefit to the wildlife in the area?

A. Grapes are a large commitment, especially if you plan to sell products from them. You can be successful with only a few plants for the family to use for grape production. A few good choices for this area would include Frotenac or Valiant. The first year the grapes would need extra care, but after that they would be more self-sustaining. Deer will feed on the foliage. If you decide to grow your grapes for commercial use, register  your acreage with the driftwatch website at  www.fieldwatch.com to help avoid problems from drift since grapes are very sensitive to drift damage.

8. A caller has strawberries that were planted and now have very small fruits and the plants are not making runners.

A. Everbearing strawberries are typically very small for fruit size. You might try planting some newer varieties that are June bearing to get larger fruits. Some good choices would include honeoye or albion or sparkle.

9. This caller has an ash tree that is 7 years old and the tree snapped off in the wind. There is mold in the trunk and it is suckering. What can be done to plant a new tree?

A. You can get a company to come in and grind out the stump or rent a stump grinder to do it yourself. The suckers that keep growing back will continue to for a few years, they can be cut out and treated with a roundup or 2,4-D product. You can plant a new tree within just a few feet of the old tree, since this wasn’t a very large tree yet.

10. A facebook photo came in with a odd structure that appeared by a tree. What is this?

A. This would be a stinkhorn fungus. They are not harmful to the plants growing in the area. There is not control other than mechanical removal of the fungus. Do not eat these as they are not edible, they would be a poisonous mushroom.

DSCN6327
Stinkhorn Fungus

11. The last caller of the day has tomatoes in a raised bed. When they ripen for harvest, the end of the tomato seems blighted. What would cause this?

A. This is blossom end rot. It is a calcium deficiency that develops in our plants in drought situations because calcium is only available to plants after it has been dissolved in water. There is no control for this, it should only last for a few weeks early in the growing season and then the plants should grow out of it.

Problems in the Garden

Now that summer is in full swing, our gardens should be growing well now. It is at this time of the year when we always tend to see many different diseases and environmental conditions on our vegetable garden plants.

blossom end rot zucchini
A zucchini developing with blossom end rot

One of the most common problems we see early in the growing season is blossom end rot. This is an environmental condition where the end of the fruit that is not attached to the plant begins to rot away. It starts as a flat, dry, sunken brown rot on the blossom end of the fruits. Gray mold can occur in this rotten spot of the fruit, as it progresses. Blossom end rot is caused by a calcium deficiency while producing fruit. In Nebraska, there is rarely a lack of calcium in the soil, but calcium needs to be dissolved in water to be absorbed into the plant, so, it often occurs in conditions of dry soil. Blossom end rot can occur in tomatoes, peppers, cucumbers, zucchini, or watermelons.

Drought stress, low daytime humidity, high temperatures, and rapid vine growth favor blossom end rot. Applying calcium to the soil or to the plant is not beneficial. It is best to just maintain consistently moist but not saturated soil. It will also help to use organic mulch near the base of plants to keep the soils moist. Often the first ripe fruits are affected and later produce is fine. Remove infected fruits at the beginning of the season and later ripening fruits should not be affected.

Scorch is another problem we often see in the summer months, especially when the temperatures range as high as it has been recently and rain is scarce. Currently scorch has been found on bean plants. When scorch appears on our plants the edges of the leaves will turn brown and papery. Wilting and leaf scorch can be reduced with regular watering during prolonged dry periods. Mulching around the base of plants will hold moisture in the soil.

Squash bugs and squash vine borer are seen in our gardens every year. With squash bugs, we will see yellow speckling on the leaves and feeding damage can appear on the fruits. You may also see rusty colored eggs on the underside of the leaves that can be removed and destroyed. With Squash Vine Borer, rapid death and wilting of the plants will occur, once they are found in our plants, there is no cure.. These pests feed on plants in the cucurbit family, which includes zucchini, squash, cantaloupe, watermelon, cucumbers, pumpkins, gourds, etc. Squash vine borer can be controlled by wrapping the stem of your plants with aluminum foil or a toilet paper or paper towel tube to stop the females from laying their eggs on your plants. Other controls include Carbaryl (Sevin), Permethrin (Eight), or bifenthrin (Bifen), or Bt for the squash vine borer. This will need to be reapplied every 10-14 days throughout the growing season. It is best to switch between at least two of these products to avoid resistance from developing. Always follow the label recommended rates and follow the pre-harvest interval listed on the label when harvesting fruits and vegetables after using chemicals. Spray the undersides of the leaves and the base of the plant thoroughly. All sprays should be done later in the evening to avoid damage to bees and other pollinators.

The information for this article came from Nebraska Extension’s Hort Update. This is a monthly news column covering seasonal information for Nebraska’s green industry professionals. It is produced monthly throughout the year by Nebraska Extension Educators from across the state. You can subscribe to this newsletter by going to hortupdate.unl.edu and selecting “subscribe” from the top tabs. You can also get there from the Gage County Horticulture Page from gage.unl.edu