Yard and Garden: July 26, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for July 26, 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: Bob Henrickson, Horticulture Program Coordinator for the Nebraska Statewide Arboretum

1. The first question of the show was about catalpa trees. They were pruned in the past, but now they have a bunch of smaller branches growing out of the location where the branch was removed from the tree.

A. The branch that was removed was likely not correctly done. If the cut wounded into the trunk of the tree or left a stump, it would cause the tree to push a lot of new growth like suckering. Make sure that proper pruning cuts are followed and that you don’t leave a stump. Follow these steps when pruning a tree to ensure it is removed correctly with minimal damage and avoid the branch-bark collar to avoid a flush cut which will not heal correctly.

3-step pruning cut
Proper pruning cut, University of Missouri Extension

2. How do you control clover in the lawn?

A. Clover can be found in an under-fertilized lawn. It may be a good practice to fertilize at least one time a year to help the lawn compete with the clover. If treating with chemicals, the fall is the best time of year to treat for broadleaf perennials such as clover, dandelions, and creeping Charlie. Apply a 2,4-D product or one containing triclopyr twice in the fall. Mid-September and again in mid-October is best. Other IPM strategies for controlling clover include mowing high and aeration if necessary.

Co Potato Beetle Pupa 2
Colorado Potato Beetle Pupa

3. A question came in via email about orange things on potatoes. There are tiny orange bugs found on potato plants in her garden. What are they and how can they be controlled?

A. These are Colorado potato beetle larvae. Pull any off that are found and smash them or spray with sevin to control them as they emerge as beetles.

4. A caller has creeping Charlie in their yard. When is the best time to spray for that?

A. When using chemicals, the fall is the best time of year to treat for broadleaf perennials such as clover, dandelions, and creeping Charlie. Apply a 2,4-D product or a product containing triclopyr twice in the fall. Mid-September and again in mid-October is best. Other IPM strategies for controlling creeping Charlie include mowing high and aeration if necessary.

5. This caller has cucumber plants with a lot of flowers but no fruits. Why are these plants not producing fruits?

A. You should check the flowers to see if they are all male flowers or if there are female flowers as well. Male flowers just have a skinny stalk behind the flower. Female flowers have a tiny cucumber behind the flower. If male flowers are all that are present, give it time for the plant to produce female flowers. If both male and female flowers are present, there could be a problem with pollinators. Avoid spraying while bees are active, attract bees with other pollinator plants, put up a bee house to bring bees in. If you are using row covers, be sure to uncover the plants for a while during the day so bees can pollinate the plants.

6. A caller called in with a good suggestion to help with cucumber plants. He grows his on a trellis so they can get better airflow and less diseases. It also makes it easier to harvest the plants this way.

7. This caller has a small hackberry that is 12-14 feet tall with 3 trunks growing together. There are small splits all along the trunk like some type of injury, what caused this and will his tree be ok?

A. These could be spots from hail injury, even from a few years ago. There is nothing to do for hail damage. Most trees will come through just fine. If the damage is intense, the tree could have more problems.

8. Is it too late to trim lilac bushes?

A. Yes, it is too late for general pruning of lilacs. They should be pruned within the first couple of weeks following the flowering period. If a rejuvenation pruning is desired, the fall would be a good time to do that, wait until late September to mid-October for that.

9. A caller who manages a golf course has a couple of Linden trees that were under water for about 2 months this year. They sat in a flooded area of the golf course for this time in the spring. They originally did leaf out but since then the leaves have turned brown. Will the tree be ok?

A. There is likely no life left in these trees. Lindens are not adapted to have their roots that wet for that long. The trees probably had enough energy left in the roots to push out leaves but now have ran out of energy. It would be best to remove those trees and replace them with something more adapted to sitting in water from time-to-time, such as bald cypress trees.

10. The final question of the day was sent via email. This listener has a gravel driveway that is partially sloped. How can they keep the weeds out of this driveway and not harm the grass at the end of the slope?

A. Roundup 365 would be the best option for this. It contains glyphosate as well as imazapic which lasts longer than the glyphosate alone. On the label it states to only apply once a year and to “spray until THOROUGHLY WET”, so for best results spray to this extent. Soil sterilants aren’t recommended because they often run off into adjacent plant material such as grass and kills it. Always read and follow the label when using pesticides.

*Disclaimer ­- Reference to any specific brand named product does not constitute endorsement, recommendation, favoring or implied criticism if similar products are not mentioned by Nebraska Extension in Gage County.  Identifying specific pesticides are for the convenience of the reader and are generally most commonly available.  Always read and follow the pesticide label.

 

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.

Moisture Problems for Trees and Other Landscape Plants

2015-05-13 11.43.22

The excess rain this year is a change from many years where we are already worried about drought stress on our landscapes. However, excess moisture is causing problems in our landscapes this year from fungal diseases as well as nutrient deficiencies.

Chlorosis

chlorosis amy cogswell, resized
Photo of Chlorosis by Amy Cogswell

Chlorosis is a condition that occurs to many tree species with symptoms of the leaves or needles developing an abnormally light green or yellow color. Chlorosis is typically caused by a deficiency of iron in the plant tissues. With iron chlorosis, the leaves will be lime green in color while the veins of the leaves remain darker green. Chlorosis can also be caused by over-watering, over-fertilization, and damage to roots among other things. This year, with the high levels of moisture we have seen this spring and summer have led to a lot of chlorosis in trees like birches, maples and oaks.

Chlorosis happens commonly in southeast Nebraska soils because of our high pH levels. The pH in an alkaline or clay soil is higher and that high pH will tie up the iron making it unavailable to trees. Iron is sufficient in the soil but it is not available to the tree. In overwatered or compacted soils, the roots have low oxygen levels that can affect the ability of the roots to pick up iron and other micronutrients. The excessive rains this year have caused more chlorosis than other years because the roots are lacking oxygen and can’t pick up the nutrients they need. 

Anthracnose

Anthracnose is a fungal disease that affects the leaves of many ornamental trees. It is seen primarily on sycamores and maples but can be seen on many trees including oaks, ash, and walnut. It causes irregularly shaped brown areas on the leaves. The affected portions of the leaf will follow the veins and will eventually cause death of the leaf and stem tissue. This disease is primarily an aesthetic issue, it will not kill the tree, at least not in only one year of infection. Because of this, Fungicides are rarely recommended.

Anthracnose is more common under cool, wet conditions, which is why we are seeing it this year. The fungi is host specific, so if anthracnose affects your ash tree, that fungi will not spread to the maple tree. However, if the conditions are favorable for anthracnose on one host, it is likely that it will be found in multiple hosts.

There is an anthracnose found in cucumbers and other cucurbit or vine crops in the garden as welll. If your cucumbers have anthracnose on some leaves, pinch those leaves off and destroy them, don’t compost them and don’t leave them around your plants. Fungicides are not usually cost effective for home gardeners, but mancozeb or other copper fungicides can be used to minimize damage to plants if desired. Be sure to read and follow all instructions on the product label.

Septoria Leaf Spot

Septoria leaf spot is a problem showing up this year on our perennial plants including mums, coneflowers, coreopsis, blanket flower, lambs ear, and many more. This is another fungal disease showing up with all of the rain this year. With septoria, purplish to brown colored spots will develop on the leaves, sometimes completely covering the leaves. It tends to start on the older foliage of the plant, but if overhead irrigation or excessive rain events continue, it can continue to spread through the plant. If you see Septoria leaf spot in your garden, remove infected plant parts. Fungicides such as copper can be used for Septoria leaf spot as well if desired.

Septoria leaf spot can also be found in tomato plants. It will appear on the leaves as small spots with a whitish center and dark colored border. Eventually the spots can coalesce into larger spots and destroy entire leaves. It can lead to defoliation and in severe cases even death of the plants. As you see Septoria leaf spot on your tomato plants, remove the foliage. Copper fungicides can also be used but should be used at first sign of the disease to reduce the spread. Also, avoid overhead irrigation to reduce spores splashing and spreading the disease; water only at the base of the plants.

 

Think Ahead for a Fall Garden

Cold-Frame
Cold Frame Photo from Iowa State University Extension

It may seem that our gardening season finishes up as soon as it begins. This is the time, however, to start thinking about fall gardens and succession planting to extend your gardening season.

Start transplants indoors now

Fall gardening can be more beneficial than spring gardening. Some of our spring crops will actually grow better and produce better under cooler fall weather than they do in warmer spring temperatures. The weather often warms up quicker in the spring and can cause our spring crops to bolt or die early with little production. The longer, cooler fall season can be the answer to this problem.

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.

Some of our fall plants could be started indoors now to get a transplant ready for fall planting season. Broccoli, cauliflower, brussels sprouts, cabbage, and others can be started indoors now so they are ready to be planted outdoors in late summer. Some of these cool season crops need 65-85 days to maturity and may do better if they are planted as transplants. Start them indoors now to be planted in mid-August to ensure harvest prior to heavy freeze.

Order transplants and garlic now to plant in September

Some local nurseries may not carry the transplants for your fall garden later into the season. A lot of the nurseries will clear out plant inventory by the later part of June and may not have these crops available in August for fall gardening. Check around to look for local inventory and see which nurseries will still carry these crops later in the season for fall planting. If you cannot find them locally, you can order seeds or transplants from mail order catalogs or through the online shopping options.

garlic-olga-filonenko-flickr
Flickr image courtesy of Olga Filonenko per CC license.

Garlic is another crop that is planted in the fall, but it isn’t harvested in the fall. Plant garlic in October to be harvested the following June. Garlic needs to be planted in the fall because the new plants need to be exposed to cold soil temperatures for 1-2 months to form the bulb that will be harvested next summer. Even though it is early for planting garlic, you might want to order this early because garlic is difficult to find at planting time.

Plant second round of summer crops

Succession cropping, or double cropping can be done in our gardens as well. This is a gardening technique that allows a gardener to utilize a longer season of growth with multiple or the same crops. An early crop is grown, harvested, cleared off and a new one replaces that first crop. You can also do a staggered planting where you continually plant every week or 2 in the early season or plant an additional crop later in the season for longer harvest. Staggered planting can be helpful to avoid peak insect populations and avoid the majority of the damage on crops. Start your second crop in July if you haven’t already planted again.

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 5, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for July 5, 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: Laurie Stepanek, Forest Health Management Specialist from the Nebraska Forest Service

1. The first question of the show was curious about bagworms. He needs to spray the trees in his backyard but he has a coy pond nearby. Will the sprays harm the fish in the pond?

A. It would be best to use Bt on the bagworms here to ensure that if sprays get into the pond it will not harm the fish. Bt is a product that affects only butterflies and moths and won’t harm other insects or wildlife. Bt works best on young, newly emerged bagworms, but there would still be time for that product this year.

Bagworm4
Bagworm

2. A caller has willow trees that are growing on a dam for a pond. How can they be controlled?

A. Rodeo or Garlon 3A are the 2 products listed for managing woody  plants or annual and perennial weeds in or around water in the Weed Management Guide from Nebraska Extension.

3. This caller has garden plants that were chewed off by rabbits. Will these plants regrow or are they dead?

A. If there are still a few leaves left on the plant they might still regrow. However, if there is really only a stem and a tiny leaf or two, they likely won’t regrow. It is getting quite late for replanting, so it might be best to just wait and see how they regrow.

4. A caller has an apple tree that broke off at a split in the tree in a storm. Now there is a hole in the tree. What can be sprayed or put into that hole to prevent further damage?

A. It is not recommended to fill holes in the tree because that can be harmful when the tree does need to be removed. It also will not stop decay that is occurring in the tree. Decay is a fungus and it will proceed through the tree even around a fill agent. If the decay is a problem in the tree, the tree may need to be removed before it becomes a hazard.

This caller also has a maple with dead branches in the top of the canopy. What would cause that?

A. Top dieback could come from a number of factors. It could be from a canker disease that occurs on stressed trees. Canker diseases will kill branches from the point of infection outward on the branch. The only cure for a canker would be to cut out the branch below the canker. Top dieback could also be from borers or a root issue. Borers come into a stressed tree and will cause decreased flow of water and nutrients through the tree causing the top of the branches to die. If more soil is added to roots, causing decreased airflow to the roots, top dieback can occur. Root issues such as damage to the roots or a girdled root can also cause top dieback in the tree. Root issues cannot be fixed. If you notice borer holes, you can use a systemic insecticide containing Imidacloprid, such as Merit.

5. A walk-in listener wants help with identification of a weedy grass species that he is having trouble controlling.

A. This looks to be annual bluegrass, which can be difficult to control. Use pre-emergent herbicides such as Drive or Pendulum in September or use Tenacity as a post-emergent herbicide in the spring or summer. For more information, view this Turf iNfo on Annual Bluegrass Control.

6. This caller has maple trees that have limbs reaching out over his house, some of the limbs are dead. When and how far should these limbs be pruned to ensure they don’t fall on the house and cause problems?

A. It would be best to find a Certified Arborist to do this to ensure it is done correctly and to avoid damage to the house. Remove all dead branches. When shortening branches, cut back to a side branch that is at least 1/2 the size of the limb you are removing. Anytime would be ok, but the best time for a maple is later in the spring, to avoid heavy sap flow if pruned in the early spring or late winter.

7. A caller accidentally spilled hydraulic oil from his tractor onto his lawn. There is now a dead area in the soil. What is a quicker way to get grass growing back there other than to wait?

A. It might help to dig out the soil in that area and replace it with new topsoil. Dig out around the area of dead grass and dig 4-6 inches deep. It would be best to just wait until early September to do this so that it can be reseeded right away.

8. This caller wants to use Roundup around the base of fruit trees to kill grass. Should regular Roundup be used or could Extended Control Roundup be used?

A. Use basic Roundup that only contains glyphosate in this location. The Extended Control Roundup contains Imazapic for longer control and shouldn’t be used around fruits and vegetables. The label for the Extended Control Roundup states ‘Do not use for vegetable garden preparation or in and around fruits and vegetables’. Always read and follow labels of pesticides.

This caller also wanted to know what is wrong with her apricot trees, the fruits seem to be rotting as they fall from the tree?

A. This is likely due to brown rot. Next year, use orchard fruit tree sprays through the growing season. The orchard fruit sprays should be used every 10-14 days through the growing season, except during the bloom period and when ready to harvest.

9. The last caller of the day wants to know if he can eat the fruits off a purple leaf sand cherry? Also, can he shear it or is it too old to start that now that it is 5-6 years old and hasn’t been sheared yet?

A. The berries are not eaten from purple leaf sand cherry, this plant is more for ornamental value. These fruits are scavenged by birds instead. This is also a plant that won’t grow well if sheared. It is best to just selectively remove branches back to side-shoots to reduce the size.

*Disclaimer ­- Reference to any specific brand named product does not constitute endorsement, recommendation, favoring or implied criticism if similar products are not mentioned by Nebraska Extension in Gage County.  Identifying specific pesticides are for the convenience of the reader and are generally most commonly available.  Always read and follow the pesticide label.

Yard and Garden: June 28, 2019

Yard & Garden blog, 2019

This is the Q&A for the Yard and Garden show for June 28, 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: Dave Olson, Forest Health Specialist from the Nebraska Forest Service

1. The first question of the show was about a red twig dogwood that is overgrown. Can it be pruned now?

A. It would be better to wait until fall to prune it. It can be thinned by removing 1/3 of the canes at ground level. This type of pruning can be done every year to remove the oldest, least productive canes from the plant. You can also do a rejuvenation pruning on it by cutting the whole plant off 6-8 inches above ground level in the fall. This will help to bring back a deep red color in the stems that may have faded over the years. If you rejuvenate it this fall, it will not bloom next year, but should after that.

2. A caller has a couple of blue spruce trees with low hanging branches. Can those branches be removed now to make it easier to mow around?

A. Yes, you can remove those lower branches for mowing around. That can be done most anytime, but it is best in the late winter while the tree is still dormant.

3. This caller has green ash suckers that are growing up in her gooseberry bush. These have come from an ash tree that was removed a few years ago but is still suckering. What can be done to kill the ash seedlings and not harm the gooseberry bush?

A. It might help to get someone to grind out the ash stump to help fully kill the tree. If the stump is still there, the roots are likely still alive and doing what they can to bring the tree back, which includes suckering in other locations. Otherwise, you can just keep cutting the suckers off and eventually the roots will run out of energy. You could also cut back these suckers and paint the fresh cut with a roundup or glyphosate product.

4. A caller has gray bugs with long black antennae that are found in her garden. What are these and how can they be controlled?

A. These bugs could be blister beetles. They can sometimes come into our gardens. Certain years, they can be found in high population. If they are feeding on your garden plants, you can spray with some sevin or eight to control them.

She also wanted to know what would cause her iris leaves to turn yellow with brown spots in the yellow color?

A. This is likely from Iris Leaf Spot, a common fungal disease of Iris plants. This can be controlled fairly well by removing and destroying the infected plant material as it shows up. When watering, don’t water over the foliage which will spread the disease. If necessary, a fungicide such as Daconil can be used if sanitation isn’t enough.

5. This caller is trying to re-establish a new windbreak. For a quick windbreak solution, would the quick growing willow-type trees work well?

A. Willows and other very fast growing trees would not work as a windbreak, even temporarily. The fast growth in these trees would not be very strong growth and therefore it would break a lot in windy situations. It would be better to go with a larger shrub such as a viburnum or serviceberry to help fill in until the trees can grow up larger. These shrubs would block the winds quicker than some trees but withstand strong winds and storms much better than willows.

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Bindweed

6. What can be done to control bindweed in phlox?

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 stem and leaves of the bindweed to kill it. Basically, the idea is to keep it from flowering and producing more seed, hand pulling will help keep new seed from being deposited into the garden which can be viable for up to 60 years.

7. A caller wants to know if she can use the Extended control Preen on her petunias, they are not listed on the label?

A. If it is not listed on the label, you can’t use that pesticide on that plant. Stick with the general preen that has the petunias on the label to ensure correct application.

8. This caller has a pin oak tree with lower branches that are in the way of mowing. Can those be removed right now?

A. No, it is best to avoid pruning oak trees during the summer months. Oaks are susceptible to a disease called oak wilt that is spread by a beetle. The beetle is attracted to the trees after they have been pruned. Oak wilt can kill the tree if it is introduced to the tree. Wait until the fall or until the trees are dormant or early next spring before April to prune oak trees to avoid this disease.

9. A caller had her driveway lined with small mums that grew only to 1 foot tall. Over time some of them have been dying periodically throughout these lines. What could she switch to that is more winter hardy and stays at the 1 foot tall size?

A. That is a problem with some of our newer mum varieties, they just aren’t as winter hardy as they are advertised to be. The 1 foot tall size is difficult to find, I would suggest a groundcover to stay so small. Most other plants are going to be 2-3 feet tall at least. There would be some nice phlox that would look nice lining a driveway.

10. This caller has an oak tree that was pruned. The pruning is about 20 years old and has recently started oozing. What is wrong with it?

A. The tree could have borers or it could be a slime flux. It would be best to have a Certified Arborist look at the tree to determine what is causing the oozing and what can be done about it.

11. A caller has a mulberry tree with a flower bed underneath the tree. The high number of mulberries are now falling off the tree and rotting on the ground which is attracting flies. Is there anything that can be sprayed to treat for the flies but not harm the tree or the flowers growing underneath?

A. This is difficult since the fruit is already maturing and falling from the tree. If it was caught earlier, the fruits could have been quickly harvested by placing sheets underneath and shaking the branches. Once the fruits are on the sheets, they can be used or destroyed away from the tree if there are too many for consumption. Leaving the fruits to decay around the tree is attracting the flies. Using a sevin around the plants could help reduce the flies, but it won’t eliminate them entirely. Once the fruits have decayed completely, the flies should not be a problem.

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Rust on a Pear tree

12. This caller has an apple tree that gets rust even when they are spraying and then it moves onto their peach tree. What can be done for this disease?

A. Rust is found on apples, crabapples, and pears, but not on peaches. I would say there are 2 different problems. As for the rust, if the timing or chemical formulation is off a bit, the spraying will not work. Be sure to spray the trees with either copper fungicide or orchard fruit tree sprays. These sprays need to be applied every 10-14 days through the growing season starting at bud break, skipping the time frame while the trees are blooming to avoid harming pollinators. As for the peaches, it could be a fruit rot or other disease. The orchard fruit tree sprays will work on those as well, but it would be for a different disease on the peaches, not the rust.

13. A caller has a 6-7 year old apple tree that was girdled all the way around the tree this past winter by rabbits. It seems to still be growing fine, does the death just take a while after damage like this? Will it eventually die?

A. It could be ok, but most likely it won’t live through girdling all the way around the tree. If the damage was minor and the tree is able to seal up the wound, maybe it will be ok. I would say just to keep an eye on the tree and give it time to see if it gets better or worse. If the canopy isn’t full or has top dieback, you would want to remove it before it becomes a hazard.

14. This caller had large hail last week. It hit his vegetable garden. Is there anything he can do for the plants now? Will they survive and produce?

A. This depends on how badly the plants were injured and if the damage is mostly just on the leaves. It is a situation where time will tell, the damage may not be fully present for a while. There is nothing that can be done to fix this type of damage once it gets hailed on.

15. A caller has bare spots in the lawn due to shade under pine trees. What can be done about that?

A. Grass doesn’t grow in the shade. It would be best to use mulch under the trees or try to plant something else that thrives in shade conditions such as carex, sedge, or other groundcover or use shade perennial plants. Remember to plant the right plant in the right place for best growth.

16. This caller has rose with leaves that were eaten off of it. What would do that and how can it be managed?

A. This could be from rose slugs, but the damage sounds worse than what rose slugs do. It could be from Japanese Beetles. Those can be controlled with sevin, bifenthrin, or neem oil applied to the leaves. Be careful to avoid hitting the flowers with insecticide sprays to avoid injuring pollinators.

17. The last caller of the day wants to know how to renovate her strawberry plants?

A. According to John Porter, UNL Extension: She will want to manage weeds, but do nothing to disturb the plants. They should be left to grow until the end of the season. Tilling is okay around the beds, but in the beds hand pulling or minimal cultivation would be ideal to avoid damaging roots. Using a mulch like straw or woodchips can help control weeds in the bed. If the strawberries are a Junebearing variety, they are done producing for the year.  However, if they are a day neutral or everbearing variety they will have more production cycles throughout the season.