Yard and Garden: August 3, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for August 3, 2018. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am this was the final episode for 2018. It can be found again next spring on kutt995.com for online listening. If you enjoy reading my Q&A from the show each week, take my quick survey at: go.unl.edu/yardandgarden18 and be entered to win a free tree diagnostic book.

Guest Hosts: Kevin Christiansen, Horticulture Instructor at SCC Beatrice & Evan Alderman, Turfgrass Management and Horticulture Instructor at SCC Beatrice

1. The first caller of the day has a windbreak that has elms growing in it. How can he kill the elms and not harm the windbreak trees?

A. In this situation you need to use a herbicide that will kill the elms but will not be translocated through the roots into the surrounding windbreak trees. Tordon should NOT be used in this location. A good option would be either glyphosate, Roundup, or a 2,4-D product. Use these 2 products as a stump treatment on the tree just after cutting the tree off.

2. A caller has cucumbers that are blooming but are not producing any fruit yet. Why are the cucumber not producing? This caller also wondered how to control puncturevine?

A. The cucumbers could be due to no female flowers, if all the flowers are male, they will not produce any fruits. Sometimes our plants start with just male flowers and the females will come in later. It could also be due to low pollinators around the plants. If not many bees or beetles or other insects are found around the plants, they cannot be pollinated and may need to be hand pollinated. Hand pollination can be done by running a cotton swab through all of the blooms, this would move pollen from male flowers to female flowers. Puncturevine can be controlled with a 2,4-D product in the fall. Apply the 2,4-D in mid-September and in mid-October.

3. When should you transplant surprise lilies?

A. Surprise lillies can be transplanted or divided just after the flower dies back in the fall.

4. This caller has foxtail in the vegetable garden. Can anything be sprayed in the garden to control the foxtail?

A. There is nothing that can be sprayed over a garden to control foxtail and not harm the garden plants. The best option would be to use preen in the spring and summer to stop the germination of annual weeds such as foxtail. Be sure to use the preen that is labeled for use in a vegetable garden and wait until after all seeds planted have germinated. Mulch would help suppress the weeds in the garden as well. Grass clippings, straw, or other organic mulches will help keep the weeds down to help your vegetable plants grow better.

5. A caller was looking for assistance choosing fruit trees for his acreage. He also has rust on his fruit trees and wants to know how to manage it.

A. There is a great NebGuide on Fruit Tree Cultivars for Nebraska. For rust, this is not the correct time to treat for it. You can spray your trees in the spring with a liquid copper fungicide. For more on care and pest control of your fruit trees, visit: https://food.unl.edu/local-food-production

6. This caller has a windbreak of Red Cedars that are losing limbs. The trees are 100 years old and 30 feet tall. What is wrong with them?

A. This could be due to old age. It may be a good idea to start a new row of trees on the inside of the old row.

7. A caller has nutsedge in his lawn. What can he spray it with and can he still spray it?

A. Sedgehammer is the best control for nutsedge. It can still be sprayed now, however more control will be achieved if applied in the beginning of June, prior to the first day of summer. If sprayed before June 21st, nutlet production will be reduced, thereby reducing the population for the following year.

2014-10-06 15.27.18

Tree planting in the fall

8. This caller wants to know when the best time is to transplant an oak tree?

A. Fall or Spring are both good times to transplant a tree.

9. How do you control cattails and water lilies in a pond?

A. Rodeo is the glyphosate product that is labeled for use in water and it can be used on both of these weeds.

10. How can you control crabgrass and nutsedge in a lawn

A. Quinclorac can be used now for both of these weeds. Or use a pre-emergent herbicide in the spring and again in June for the crabgrass and sedgehammer for the nutsedge in June. Tenacity is another product that should work on both of these weeds.

11. A caller wants to know why we should worry about getting rid of cattails and water lilies in a pond?

A. Weeds in a pond can strangle the waterways or destroy habitat for fish. Some plant life along the edge of the pond can be beneficial, but too much can be a detriment.

12. This caller has lilies with caterpillars in the stem. What are those and how can they be destroyed?

A. This is likely a cutworm. Sevin or eight or Bt applied at the base of the plant can help kill these pests before they damage your plants.

13. When is the proper time to apply a winter fertilizer on a lawn?

A. Fall fertilizer can be applied in late August to mid September and the winter fertilizer can be applied in the middle to late October. It is no longer recommended to apply the winter fertilizer in November as previously recommended.

14. A walk-in listener has a weed they need identified and they need to know how to control it?

A. This is a weed called nimblewill. It is a warm-season grassy weed. It can be treated either with Roundup or Tenacity. If you use Roundup and reseed, apply the roundup now, while the nimblewill is still green and then overseed in a couple of weeks through the end of September.

15. This caller has spaghetti squash that was looking great and then one day it just died. What caused it to die and how can the other plants be protected?

A. This is likely due to squash vine borer. You can use sevin or eight to protect your plants from the squash vine borer. Be sure to apply it at the base of the plant where the plant comes out of the ground. These chemicals will need to be reapplied every 10-14 days throughout the growing season to protect the plants. Otherwise, you can wrap the base of the plant in aluminum foil to prevent the borer from getting into the plant.

16. A caller has watermelons with yellowing leaves. This has happened to his plants 3 years in a row now, he does rotate the crops in the garden. This damage starts at the base of the plants and will eventually kill the whole vine. He has mulch on the garden and waters slowly with a hose for 2 hours at a time. What is causing this problem? Also, when do you transplant iris?

A. This looks to be alternaria leaf spot. He is doing many things to prevent this disease already with mulch and his watering practices. It might be beneficial to try a liquid copper fungicide this year and next year as soon as the symptoms begin. Iris can be transplanted in the fall, September or October would be best.

17. A walk-in listener has a tree they want identified and they want to know why it keeps suckering and what they can do with the suckers?

A. This is a silver maple tree, they are prone to suckering. Suckers should be just cut off as they grow to reduce the amount of energy they take from the main tree. Do not treat the suckers with anything as that could injure or kill the main tree because the suckers are growing off the main tree roots.

18. This caller wants to know why their pepper plants are not growing well?

A.The peppers are planted too closely to a black walnut tree and will not grow well in that location. Black walnut trees produce juglone, which is basically a naturally produced weed killer. Certain plants are more sensitive to juglone, tomatoes and peppers are quite sensitive. The garden should be moved to at least 50 feet from the black walnut of the plants should be grown in a container or raised bed to avoid problems with the juglone.

19. The final caller of the year has hostas planted in a rock garden and they are not growing, they are still small like they were just planted there.

A. The rock garden may be too hot for the hostas and the rocks do not provide any nutrients back to the plants. It might be best to switch to a wood chip mulch to help reduce the heat and add some nutrients and organic matter to the soil.

2015-07-30 16.59.55

Bindweed

This caller also wanted to know what to do to kill the bindweed growing in her Iris beds?

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.

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Yard and Garden: July 6, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for July 6, 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: Dennis Ferraro, Wildlife Specialist from UNL

1. The first caller of the day wants to know if borers from ash trees can get into his walnut trees?

A. Some native borers can be a problem in both ash and walnut trees, such as the redheaded ash borer which is a common borer in many of our trees in Nebraska. When the Emerald Ash Borer gets to southeast Nebraska, it will not be able to. EAB is a pest in Ash trees only.

He also wanted to know how to move woodchucks and not kill them?

A. Live trapping will work for woodchucks. Use cucumbers or corn to bait them and wire the trap open for a few days before actually activating the trap because woodchucks are very cautious and will not be trapped the first time or 2 into the trap. The woodchuck can then be relocated to within 100 yards of the trapped location. State regulations prohibit relocation farther than 100 yards. It would also work to change their nesting location. This woodchuck is found under a building, so if you can chase it out during the day then pack the hole tightly with road gravel will prevent them from coming back. For more information, visit the UNL Wildlife website on Woodchucks.

2. A caller has heard that bull snakes will keep rattle snakes away. Is this true?

A. These 2 types of snakes do get along but bull snakes are more aggressive hunters and can out-compete rattle snakes. Because of this, rattle snakes usually relocate to find food.

3. This caller has tomatoes with bumps along the stem of the plant. What is wrong with the plant?

A. There is nothing wrong with tomatoes that develop bumps along the stem. These are aerial roots which are common.

4. A caller has a white powdery substance on her peony plants. What causes this and how can it be controlled?

A. This is most likely powdery mildew on the peony plants. It is a common disease we see this time of the year. There is no need to treat the plants for it right now. The best control for powdery mildew is to cut off the plant in the fall when it dies back and destroy the infested plant material so the disease cannot overwinter. It will not kill the plants.

5. This caller has tomato plants with leaves that are turning yellow and the plant is not producing tomatoes, any flowers produced fall off. What is wrong with his tomato plant?

A. This is likely due to environmental stress or possibly Septoria leaf spot. Make sure that the plants are watered 1 inch of water per week, they have mulch, and they are being watered from below. If desired, a fungicide can be applied. For more information view this NebGuide on Leaf and Fruit Diseases of Tomatoes. The poor pollination is common this year due to the heat. Give the plants some time and they should start to produce.

6. A caller has a sycamore tree that is shedding bark. What is wrong with the tree?

A. It is normal for sycamore trees to lose some bark. It is a tree that has a camouflage bark appearance due to the fact that it sheds some bark. Nothing to worry about or to do to fix it.

7. This caller is growing petunias in a hanging basket and the leaves are turning yellow. What is wrong with them?

A. This could be due to environmental stress. Make sure they are kept watered and placed in a location where they get full sun. It might also be from spidermites, look closely at the plant to see if there is any very fine webbing. If so, use a strong spray of water to knock the spidermites off and kill them.

8. A caller has bindweed in his garden and in his lawn. What can be done to control it?

A. In the garden, 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. In the fall, you can spray the lawn with a 2,4-D product.

9. How do you control purslane in the garden?

A. Purslane easily reproduces from cuttings so avoid hoeing or weed trimming through it while leaving pieces of the plant laying around on the ground throughout the garden. Purslane doesn’t like to be smothered, so a heavy mulch layer on the weed will help.

Gorgone Checkerspot Caterpillar

Gorgone Checkerspot Caterpillar

10. This caller has tiny, dark colored worms on her black-eyed Susan plant. She has used some Eight but she still has some. The leaves are also turning gray, how can she control the caterpillar?

A. This could be a checkerspot caterpillar. It is commonly found on sunflower, which is a closely related species of plant to this black-eyed Susan. This becomes a good pollinator butterfly. If she can relocate the caterpillars it would be best, or the Eight will just take some time to fully work on the caterpillars. The gray on the leaves is likely due to downy mildew or powdery mildew, not the caterpillars. Caterpillars will only chew holes out of the leaves, not leave any gray coloration to the leaves. Downy or powdery mildew are not very harmful to the plant and don’t need to be sprayed. In the fall, cut down the plant and discard the infected plant material so the disease is minimized for next year.

11. A caller has an ash tree that is about 15 years old and the outside leaves are now turning brown. What is wrong with it?

A. This could be due to leaf scorch due to the hot, dry conditions we have been facing lately. The tree should be fine, it will likely look rough the rest of the year. Make sure the tree has a mulch ring and that it is being watered for about an hour weekly with a sprinkler or slow trickle from the hose.

This caller also wondered about cougars in the area. He said he has seen a cougar with 4 cubs in the area. Will the cubs all stay here or will they move through to somewhere else?

A. Males can travel many miles and across the country. Females will stay around if there is food available and if a male doesn’t chase the female cubs away. The male cubs will likely move on when they get old enough to travel alone.

12. A caller has a tree that is pushing its roots up to be exposed out of the soil. What can be done about this?

A. Mulch will be the best option for these roots. The mulch will keep you from mowing over the roots which can damage the roots. Do NOT add soil on top of these exposed roots as that can limit oxygen for those roots and eventually kill the tree. You can make the area into a perennial garden under the tree, but do not raise the soil grade to do so and do not damage the roots to do so.

13. The final caller of the day wants to know why black crappie would be larger than white crappie?

A. This could be due to genes. The color gene may be linked to the size genes. So as the color is changed genetically, so is the size. It could also be that the predators in the area this caller was fishing in preferred eating the white crappie rather than the black crappie, causing only the smaller white crappie to be left with the larger black crappie. There are many factors that could lead to this difference in size between the 2 different colored crappie.

Yard and Garden: June 8, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for June 8, 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: Donnie Engelhardt, Assistant Water Resources Director, Little Blue NRD

1.The first caller of the show heard of a chemical that can be used to treat bindweed that started with a Q. What is that product?

A. Quinclorac is the active ingredient in a product called Drive. It is effective at controlling bindweed. However, this product is only labeled for use in lawns and cannot be legally or safely used in landscape beds or vegetable gardens.

He also is having a problem with his peach tree, it didn’t leaf out on the one side. The damage is also seen in some hydrangeas planted nearby. What is causing this?

A. This could be due to herbicide damage. If multiple types of plants in different families, genus’, and species are all affected the same it is often due to herbicide drift. There is nothing that can be done now to fix the problem, leave them to see if they grow out of the damage.

This first caller’s final question is that he has 3 pear trees that he ordered from a mail order catalog and one has not leafed out still. Is it dead?

A. This one that died could have dried out during transport. I would assume by now it would have leafed out if it was still alive. Scrape the bark off some of the smaller branches, if they are green there is still life in the tree, if it is brown, the tree is dead. Also, if the branches bend rather than break they are still alive.

2. A caller is looking to plant some new trees for shade, preferably something fast growing. When should they buy and plant these new trees?

A. Purchase your plant material when you are ready to plant. If the plant has to sit in the pot longer, it can lead to more problems with it drying out. The best times to plant a tree would be either in the spring or fall. At this point, it would be best to wait until fall, like September – later October. Planting now would be difficult to keep the tree watered through the heat/drought of the summer. Fast growth is not always the best option. Fast growing trees are not as strong as the slower growing trees and tend to break more in storms. Slower growing trees can actually put on quite a bit of growth in a few short years if they are kept with a 2-3 inch mulch ring and kept well watered. For good tree choices, view this guide from the Nebraska Forest Service.

3. This caller has Iris’ that have finished blooming, can they be cut back now? They also have some mums that died over the winter, why is that?

A. Once Iris’ and peonies’ have finished blooming for the year, the flower stalk can be cut off at the ground level. However, the leaves need to be left there to build energy in the roots for next spring. Some mums are just not as hardy as believed. Many gardeners struggle with maintaining their mum plants over the winter due to repeated freezing and thawing cycles through the growing season as well as wet, heavy soil or lack or snow cover. Longevity of the plants can be enhanced by planting them in a location that is more protected from north winds, discontinuing fertilization by the end of July to reduce new growth at the end of the season, adding several inches of mulch to the soil around the plants through the winter months, and cutting the plants back in the spring rather than in the fall.

4. Should the blooms of small tomato plants be pinched off?

A. Removing those blossoms until the plants get a little more growth on them will help the plants develop more roots and more shoot growth before pushing so much energy into producing the fruits. Wait until they get a little bigger before allowing those flowers to develop into fruits.

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Redbud Tree

5. A caller has a redbud tree that was planted last year and has not leafed out yet this year. It is, however, producing suckers at the base of the tree. Can those suckers be grown into a new tree? Also, how should trees be fertilized?

A. This could be a winterkill issue. Be sure to purchase redbuds from a local source. Often box stores purchase redbud trees from a Southern source and send them to all stores in the United States. If a tree was started further south than where it will be planted, it will not adjust well to the change in climate from the south to here. The sucker will grow into a new tree. Redbuds will do better with this than some. Often the suckers from a tree may not be as strong as the main tree and will not do as well, but with a redbud it should be fine. Fertilizer is rarely needed for trees in Southeast Nebraska. I would especially avoid fertilizer on a stressed tree, such as this redbud. Fertilizing a stressed tree will lead to further stress.

6. When is the best time to prune suckers from the maple trees and when is the best time to prune the lower branches from a spruce tree so the mower can fit below it?

A. Anytime is a good time to prune suckers from a tree. It is best to just continually prune them off as they form. If you leave them, they take energy from the tree. You can prune spruce trees most anytime of the year. However, if you are just looking to prune them so you can mow under the tree, if you leave them the tree will provide it’s own mulch and the grass will not grow under the high shade of the tree.

7. This caller wants to know what to do with peonies now and if ants are needed for the flowers to open on a peony?

A. At this point with a peony, cut off the stalks of the flowers and leave the leaves there. The leaves should be left to grow and produce energy for the plant so it can come out and flower early next spring. Leaves of peony plants can be removed in the fall when they turn brown and die back naturally. No, ants are not necessary for the buds of peony flowers to open. That is just a myth because ants are commonly found on the flowers, but they just like the sweet nectar.

8. A caller planted mums last year, they looked great through the season. This year only 2 came back. What is wrong with them?

A. Some mums are just not as hardy as believed and they often die due to winterkill. Many gardeners struggle with maintaining their mum plants over the winter due to repeated freezing and thawing cycles through the growing season as well as wet, heavy soil or lack or snow cover. Longevity of the plants can be enhanced by planting them in a location that is more protected from north winds, discontinuing fertilization by the end of July to reduce new growth at the end of the season, adding several inches of mulch to the soil around the plants through the winter months, and cutting the plants back in the spring rather than in the fall.

9. The last caller of the day has peppers planted in a mineral tub that are looking wilted. They are green and growing well but have droopy leaves. What is wrong with them?

A. Through discussion, it was noted that these peppers are planted in a container with soil from the backyard, not potting soil. It would be best to use a soil mix rather than soil from the ground. Potting soil has more nutrients available and is more porous for better plant growth. Adding fertilizer to his plants may help.

Yard and Garden: March 31, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for March 31, 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: Natalia Bjorklund, Nebraska Extension Educator in Dodge County

1. The first question was when can we begin applying crabgrass preventer and fertilizer to our lawns this spring?

A. These are both best applied in late April to early May. Crabgrass will not germinate until the soil temperatures are consistently at 55-60 degrees Fahrenheit.

2. A caller wanted to know if he should mulch his asparagus and if he can use ash wood mulch around his asparagus?

A. Yes, mulch is one of the best ways to manage weeds in an asparagus patch. Ash wood chips would be fine. You do want to avoid Walnut wood chips because walnuts produce juglone which is a chemical produced by the tree to act as a weed control for nearby plants. This helps walnut trees with competition in the wild.

3. This caller has a goldenrod that has grown too large and messy for the area where it is planted. How can it be killed and what Goldenrod would be a better choice for a less messy plant?

A. 2,4-D or simple hand removal should kill the plant. When purchasing a Goldenrod plant in the future, any of the varieties would be better than the straight species. Fireworks is a nice, open goldenrod. Wichita Mountains and Baby Blue would be good choices as well.

4. Is it too early to transplant hostas? When should you cut back warm season grasses?

A. Wait a couple of weeks to transplant the hostas until the soil has warmed up a little more. You can cut back the ornamental grasses anytime now. It is better to get the old growth cut off before growth resumes so you don’t cut off the new growth. For ease of cleanup with the ornamental grasses, wrap string or twine around the plant before cutting off the old materials so it stays together when taking to the compost pile.

5. A caller wanted to know how and when to prune roses?

A. Wait until a little later into April to start pruning them. It depends on the type of rose to know how to prune them. This sounds like a climbing rose which can be pruned back about 1/2 to reduce the size. Wait until they start greening up to know which areas of the canes have died back, the dieback should be removed as well. If the canes are long and lean over mowing areas or other things, they can be tied up to a trellis.

6. This caller wanted to know how to get rid of cockleburs?

A. While talking with the caller, it came up that the plant had very small yellow flowers on it and there were spines over the plant except right at the soil surface. This plant is in fact buffalobur, not cocklebur. These are easily pulled up if you pull where there are no spines. A 2,4-D product could also be used if there was a large amount of them in the lawn.

buffalobur, Howard F Schwartz, Colorado State Univ, Bugwood

Buffalobur plant from Howard F. Schwartz, Colorado State University, Bugwood.org

7. A caller wanted to know if they should water in their crabgrass control?

A. The label will explain to you how a product should be applied for best efficacy. Always read and follow the label instructions to apply correctly. For many of the crabgrass preventers, they would need to be watered in, but again, check the label to be sure.

8. When should asparagus be fertilized?

A. Apply a general fertilizer or a composted manure to the bed after the last harvest or sometime in the fall.

9. This caller has mulberries growing in the windbreak. After they are cut down, what kind of stump treatment should be done to keep them from regrowing?

A. 2,4-D concentrate should be used as a stump treatment. This will take multiple applications and will be more effective if done in the fall. Each time the 2,4-D is reapplied it should be applied into newly drilled holes or to a freshly cut area of the stump.

10. A caller has cedars growing in their landscape. Under the cedars there is bare ground. What can they plant in that area to avoid weeds coming in?

A. The cedars are going to keep that area quite dark and the cedars will take the majority of the water in the soil so mulch would be a good alternative. If plants are desired, use a shade tolerant groundcover such as wintercreeper or vinca vine or perennial plants such as bleeding hearts, hostas, coral bells, jacob’s ladder, and others.

11. This caller has tiny cedar trees coming up throughout the lawn. How can they be controlled?

A. Cut them off at ground level. If a cedar is cut below any lateral growth it will not regrow. Mowing over them wouldn’t be low enough.

3-step pruning cut

Proper pruning cut, University of Missouri Extension

12. When is the best time to prune a maple tree that had a branch break in a storm?

A. As soon as the storm has passed and it is safe to do so, you should remove a branch that broke in the storm. If the damage occurred in a winter storm, let the ice and snow melt off first. Then, hire a certified arborist to come out and make a good pruning cut so that the tree can seal off the wound quickly and fully.

13. A caller has a hibiscus tree that is turning yellow and many of those yellow leaves are falling off the tree. It was moved indoors during the winter months in an area of the house with low sunlight. What is wrong with it and will it survive?

A. Hibiscus plants would need more sunlight than what it has received through the winter. It should be fine once it gets more sunlight. As the days get warmer, you can move it outdoors for more intense sunlight. It should be fine once it gets moved to better growing conditions.

14. This caller has a weeping willow tree that they would like to prune up a little. When can they prune it?

A. The weeping branches shouldn’t be pruned up too much or they could lose their weeping habit. Willows tend to have a heavy sap flow in the spring if they are pruned then, so it would be best to wait until later fall to prune a willow.

15. This caller has grasses that are coming up among the gravel paths around his daylily patch. What can he use to prevent those plants from coming up?

A. Preen is a great way to stop the germination of annual weeds, such as many of our weedy grass species. If they come up before the preen gets put down or if they grow as a perennial weed, you can use a post-emergent herbicide. If it is a grass that is growing out of place among daylilies, you can use Grass-B-Gon or a similar product to kill grasses.

henbit, steve dewey, Utah State Univ, Bugwood

Photo of henbit is from Steve Dewey, Utah State University, Bugwood.org

16. What can be done to manage henbit?

A. At this time of the year, there is nothing very effective at controlling henbit. Henbit is a winter annual plant, meaning that it germinates in the fall and flowers and produces seed in the spring. It dies with the summer heat. As we are now seeing the purple flowers from henbit, there is no need to control what you are seeing. The seed is already present in the lawn for next year and what you would be spraying will die soon. You can hand pull it now and spray with a 2,4-D product late in the fall.

17. This caller has moon flowers that had a lot of hornworms on them last summer. What can be done this year to reduce the number of hornworms?

A. Just because there were hornworms there last year doesn’t necessarily mean you will have a lot this year. Hornworms are sporadic pests. They are easily controlled by hand removal. You can also use sevin or eight or any other general insecticide. Use Bt to protect other pollinators as Bt is only harmful to insects in the order Lepidoptera which includes butterflies and moths.

18. What do you do for bindweed in a vegetable garden?

A. If you haven’t planted yet this spring, you can roundup the plants before you prepare the soil for the summer vegetables. The plants will probably still be a problem later in the year as this is a difficult pest to control. When it comes back in the summer, you can carefully use roundup through the growing season. You can paint the glyphosate product onto the leaves of the bindweed avoiding spraying the desired plants.

Summer Vining Weeds

2014-06-12 16.08.12

It is summer. Our gardens are out in full force and finally beginning to produce edible products. One of the biggest problems in gardens, are the weeds. There are many different types of weeds that come into our gardens, and control of these pests is very difficult.

2015-07-30 17.00.35

Bur Cucumber vine growing on a Blue Spruce

Wild cucumber and burcucumber are two very similar vining weeds that can be found in your vegetable garden, flower garden, and growing up the sides of trees in a windbreak. These vines looks a lot like a cucumber vine that we intentionally grow in our gardens. The wild cucumber has deeper lobes than burcucumber but both will vine up and hold onto plants and other objects, such as tomato cages, with tendrils.

Bindweed growing on a Peony

Bindweed growing on a Peony

Bindweed is another common problem anywhere in the landscape. This weed has arrowhead shaped leaves and a small, petunia-shaped, white or pink flower. This weed vines and holds onto plants with the stems of the vine rather than using tendrils. Bindweed is an invasive weed that can climb up on your plants and cause decreased growth and other issues as the bindweed covers the leaves and plants.

Good control for either of these vining weeds would include many different broadleaf herbicides. If applied early in the spring or late in the fall, 2,4-D can be used for both of these weeds. 2,4-D should not be applied when the temperatures for 72 hours are predicted to be above 80 degrees Fahrenheit. Products that contain the active ingredient of Triclopyr will also work for these weeds and can be used if the temperatures for 24 hours is predicted to be below 80 degrees Fahrenheit. If the weeds are growing in and among other desired plants, the best option would be a stump treatment after cutting the weed back or painting it on the leaves of the weed being careful to not get the herbicide on the desired plants.

In a vegetable garden, most herbicides are not advised for use due to the movement of the pesticide. Broadleaf herbicides would work for these vining weeds, however, they would also cause damage and possibly death of the crops growing in your garden because most of our vegetable garden plants are broadleaf plants as well. These herbicides can spread to our desired vegetable plants through direct spray, wind movement, through the soil, and by turning into a gas and moving toward the desired plants.

The best control for many weeds in our vegetable gardens would be mulch and hand pulling. Good mulch choices include straw, hay, wood chip mulch, or grass clippings. Be cautious when using grass clippings on your garden. Many herbicide labels now have more conservative recommendations that state that grass clippings from lawns to which a herbicide has been applied should never be used as mulch. If this is stated on the herbicide label, that must be followed. If the label does not state this, it is recommended to wait 3-5 mowings from application of herbicides to use of the mulch. The safest option is to avoid using grass clippings on your gardens if the lawn has been treated with herbicides that growing season. If you are unsure of where the clippings came from or when or if they have been treated this season, avoid use of these clippings as mulch to avoid any contamination from the herbicides.

Yard and Garden: June 26, 2015

Yard and Garden Green Logo

This is the Q&A for the Yard and Garden show for June 26, 2015. 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, 2015. 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 from Nebraska Extension in Lancaster County

1. A caller has a pine tree with needles that are turning brown at the bottom of the tree. What would cause this?

A: There are a couple of common fungal diseases on pine trees, needle blight and tip blight. Both of these diseases will start from the base of the tree and move upward. Depending on the species of tree, it could also be pine wilt, but this disease progresses rapidly, causing death in only a few months. There are fungicides to be used for needle and tip blight, but they are best used in May and June. Neither of these fungal diseases should kill the tree in one growing season. This publication from the Nebraska Forest Service, Diseases of Evergreen Trees, shows pictures of both diseases and pine wilt and goes over treatment methods.

2. This caller has tomatoes that have black specks on the leaves which eventually turn yellow and die, but there are no specks on the tomatoes themselves. She was also curious why it makes a difference to water from below rather than above?

A: This would be a fungal disease called black speck or black spot. It is best controlled through good sanitation practices such as watering from below the plant, removing infected leaves as they are first seen on the plant, removing plants in the fall after the growing season, avoid crowding plants, rotating plants each year in the garden, etc. There is a great NebGuide on Leaf and Fruit Diseases of Tomatoes that will be helpful with many of our tomatoes this year with all of the rains as we are seeing many more leaf diseases. Watering from below the plant helps reduce spores splashing from plant to plant and from the soil to the plant. Watering from below also helps to keep the leaves dry throughout the day and into the night to reduce leaf wetness and humidity in the plant which is conducive to disease development.

3. A caller has a bur oak that is 15 feet tall with leaves that are curled under. What would cause that?

A: This could be herbicide damage from a 2,4-D product. It could also be from aphids or lacebugs. To determine if it is due to insect feeding, look on the underside of the leaves for tiny, green bugs, lace-like bugs, or frass. If it is aphids, they can be controlled with many general insecticides. Lacebugs rarely warrant insecticides as their damage is minimal to the tree. If it is herbicide drift, the tree should grow out of it, depending on severity of damage.

Bagworm

Bagworm

4. Is it time to spray for bagworms yet?

A: They have not yet begun to emerge in Southeast Nebraska. They are behind in their development this year due to the cool spring. They should be emerging in the next week or two. Ensure that the immature bagworms are active on your tree before treating to get best control from your pesticide.

5. Another caller wanted to know if it is illegal to use rainwater in Nebraska?

A: No, Nebraska does not have a law to prohibit the catching and use of rainwater, as some other states do. Rainwater is a good use of extra water to avoid so much runoff and contamination to the water supply. Be careful to not use rainwater on vegetable crops to avoid contamination from non-potable water.

6. This caller has a Kentucky coffeetree that was planted in the right-of-way by the city within the last 2 years. The bottom of the tree has leaves and new growth, but the top of the tree does not. Will it survive?

A: This tree probably is having troubles with establishment or may have been planted incorrectly. Due to this, the top of the tree is not receiving water and nutrients from the roots. It can be pruned back to the growth with possible success. Be sure to watch for a new leader to develop or you may have to start a new one to help it grow taller as the central leader will be pruned off of the tree.

Photo by Howard F. Schwartz, Colorado State University, Bugwood.org

Yellow Nutsedge Photo by Howard F. Schwartz, Colorado State University, Bugwood.org

7. How can nutsedge be controlled in lawns?

A: A product that is specific for use on sedges can be used in the lawn with no harm to the turfgrass. The most commonly used product for yellow nutsedge is Sedgehammer, it should be applied multiple times throughout the growing season, as new plants come up. It is better to spray with Sedgehammer early in the life of the new plant to reduce nutlet production and reduce the size of the plant.

8. A caller wondered when the best time is to prune an oak tree?

A: It is not advisable to prune oak trees during the summer months to avoid chances of getting oak wilt in the tree. The best time to prune oaks, and many of our deciduous trees, would be in the dormant season, such as November.

9. A caller has a fescue lawn that is getting yellow in spots. What would be the cause of that?

A: This year we have faced many days of cool, wet, cloudy weather which is favorable to many turfgrass diseases. This sounds like it is either brown patch or dollar spot disease. Brown patch has tan colored lesions on the leaf blades that have a dark margin around the tan spot. Dollar spot would just be tan spots in the lawn that are typically half-dollar sized but you can see many dollar spots coalesce into one larger spot. As the weather dries out and warms up, the fungus should fade in the lawn, or you can use fungicides in the lawn if necessary.

10. A caller has bindweed in the lawn. What can be done to control it?

A: A herbicide that is just for broadleaf weeds will work on the bindweed and not harm the lawn. Triclopyr is a great choice to use. This is commonly found in brush killer, poison ivy killer, and clover killer in the stores. Make sure that the temperature on the day of application is below 85 degrees Fahrenheit to reduce the risk of harm to non-target plants.

11. A lady has cucumbers that are flowering with no fruits developing. What would cause that?

A: Cucumbers have both male and female flowers on the same plant. Early in the season you may see development in only male flowers with no female flowers to produce no fruit. The female flowers will have a tiny cucumber structure at the base of the flower. This also could be due to low pollinator presence in the garden. Rainy days and hot days discourage pollinators. Give the plants more time, they should begin to produce female flowers and fruits soon. Hand-pollination may also be necessary if it is due to low pollinator presence. To hand-pollinate, take a Q-tip and touch the pollen of all of the flowers.

12. A caller has a clematis plant that is dying back, causing all of the leaves to turn brown.

A: Clematis commonly gets a fungal root and crown rot. If this plant was in a location where water sat this year with all of the heavy rains, it may have caused this fungal disease to occur. Cut the plant back to the ground and see if it will grow back, if not, you will need to replant.

13. This caller has Iris plants that have completed their blooming period for the year. Can these be cut back now?

A: No, all spring blooming plants need to be left, without being cut off, for the remainder of the summer until their foliage turns brown in the fall. This allows the plants to make sugar throughout the summer months to have a starting supply for early spring blooming next year. The flower stalks can be removed after the flowers are done.

14. A caller has patches of clover in the lawn. What can be done for management for the clover?

A: The best time for treatment of clover is in the fall with a Triclopyr or 2,4-D product. At this point, the temperatures are too high for herbicide control without possible harm to non-target plants. Both of these products can turn into a gas and move to non-target plants if temperatures are above 80-85 degrees Fahrenheit, the 2,4-D can volatilize for up to 72 hours. Be sure to mow the clover prior to herbicide treatment to mow off the flower blooms and cause less harm to bees.

15. A caller has grass planted in late March and added more seed later in the spring. She used a starter fertilizer and covered the areas with straw, and now there are brown spots appearing in the lawn. What would be causing that?

A: Brown patch disease is common on young seedlings of tall fescue. Look for irregular shaped tan spots with a dark margin to know if it is brown patch. Bayleton is a good fungicide that may still be effective on this lawn. Also, remove the excess straw to reduce disease problems.

16. That same caller has crabgrass coming up around her trees. Can she use roundup to control it?

A: Roundup can be used around the base of trees with minimal damage to the trees. A better option would be to use a post-emergent crabgrass herbicide such as Dimension or Fusilade.

17. A caller wanted to know if it was allowable to use Grass-B-Gone in their sweetcorn?

A: No. Grass-B-Gone kills all types of grasses, including sweetcorn. Also, Grass-B-Gone is not labeled for use in a vegetable garden.

18. A gentleman has mock orange and bridal wreath spirea. When can these plants be pruned?

A: Both of these plants have just finished blooming for the year so they can be pruned now. Remove no more than 1/4 of the plant in a growing season. This can be done by removing the largest canes at the base of the plant. If it is too tall, you can remove 1/4 of the height, if it is a 4 foot tall shrub you can prune it back to 3 feet tall.

19. A caller wanted to know what to do for management of dandelions in their lawn?

A: Dandelions are best controlled in the fall with a 2,4-D product.