Yard and Garden: June 22, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for June 22, 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: Kathleen Cue, Dodge County Extension Educator

1. The first caller of the day has cauliflower that is turning purple in the garden. What is causing this and can it still be eaten?

A. This is a response to the heat. For next year, blanche the heads just after they begin to form by tying the large leaves up around the cauliflower heads to protect them from the sun or purchase self-blanching varieties. This cauliflower can still be eaten even though it has turned purple.

2. When is the best time to move asparagus?

A. Spring would be the best time for planting asparagus. It is more beneficial to just start a new asparagus patch rather than transplanting. It would be difficult to get all of the plant and there are a lot of newer varieties that will do better with heat and other conditions. If you transplant what you already have growing, it is still best to wait 3 years before heavy harvest again, so it would be beneficial to start over since this asparagus bed is already 20 years old.

3. A caller has nutsedge in their lawn, how can it be controlled? Roundup didn’t seem to work for it.

A. Roundup would not be effective in this situation because roundup is for grass control, while nutsedge is a sedge. For best control of nutsedge, it is best to use either Sedgehammer or Tenacity. Both of these chemicals should be effective, but they should be applied prior to the first day of summer to reduce the population for next year. Also, nutsedge tends to grow in areas of the lawn where the soil is compacted or water tends to sit, reduce the compaction and get the turf growing better to control the sedge better.

Yellow Nutsedge-Howard F. Schwartz, Co. State Univ, Bugwood

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

4. This caller has a few walnut trees that the tops look good, but near the base of the trunk the tree is losing bark. He recently added some soil and river rock around the trees. Will the trees survive?

A. When adding soil and rock around a tree that had been planted for a while, it changed the grade around the trees. This can lead to many problems with the tree because it makes the tree too deep in the soil, especially after the roots were at a higher level in the soil for multiple years. This will lead to the death of these trees. The bark could be coming off because of the death beginning in the tree or it could be due to possible damage to the roots when the soil and rock was moved in. Either way, the trees will die. Enjoy them until they do or until they become a hazard to homes, cars, or people found underneath them.

5. What would be a good replacement tree for scotch and Austrian pines?

A. Diversity is a good thing to remember when planting a new trees. Diversity includes species and age of trees. This caller has a great deal of trees to replace in a CRP, it is advised to not replace all of these trees at the same time so they have a diversity of age as well. Good choices include Douglas fir, concolor fir, hemlock, eastern red cedar, blue spruce, black hills spruce, Norway spruce, and Ponderosa pines.

6. A caller has a windbreak with bagworms. Is it too late to spray this year? What should he spray with?

A. We should be ok in the window to spray for bagworms. It is best to spray after the bagworms have germinated for the year until when the bags have developed over 1 inch in length. Once the bags are larger than 1 inch long, the chemicals will not be very effective. Tempo or Bt products would be the best choices for control of bagworms, but most any general insecticide will work.

Bagworm4

Bagworm

7. This caller has a 20-year-old red maple that only has leaves on the west side to cover only 1/4 of the tree. What is wrong with the tree?

A. When that much of the tree has died back, it will not recover. It should be removed to reduce the hazards that will appear from a dead tree.

8. A caller has a newly planted blue spruce. How long should they maintain watering the tree? Should it continue through the winter months?

A. Newly planted trees should be watered throughout the growing season, and even during the winter. If we don’t have a lot of snow cover through the winter months, it is important to water an evergreen tree about once a month on a warmer day. When watering in the winter, water in the early to mid-day to allow all of the water to soak into the soil rather than freeze up on top. It would be best to continue watering this tree at least for 3-5 years on a regular basis. However, even a 30-year-old tree needs to be watered some in years of drought. It would be best to always continue to water this tree, even if only sporadically.

9. This caller wondered if adding drain tiles when adding a raised bed around an established tree would help it to survive with this practice that is not recommended?

A. Adding a raised bed to an existing tree is not an issue with drainage. Adding more soil to where a tree is already living can decrease the amount of oxygen that the roots are able to get which can then kill the tree. Also, adding this soil make it so that the trunk of the tree is underground which can decay the trunk and lead to crown rot or other bad conditions that also lead to death of the tree.

10. A caller has a pin oak that the roots are starting to pop out of the soil around it. What can be done for it?

A. Wood-chip mulch can be used to cover up the roots as they show up out of the soil. Do not add soil or increase the soil level. Avoid rock mulch as it can be too hot for the plant. Adding a mulch over the roots will prevent you from mowing over the roots and injuring them. Plants can be planted among the roots as well, but don’t add soil to do that.

11. Is it too late to prune lilacs?

A. Lilacs will begin producing flower buds for next spring shortly after they finish flowering this year. They should be pruned within a couple of weeks after blooming has finished in the spring. They can be pruned this late, but it will reduce the flower production for next year.

12. This caller has lilacs that have never been pruned for many years. How, when, and how much can she prune now?

A. A rejuvenation pruning may be beneficial for this situation. Older lilacs, if never pruned, have unproductive wood. This will lead to less leaf production, less flowering, and often much of the leaf and flower production will be just at the top 1/3 of the plant. When this happens, it is best to just prune the lilac off 6-8 inches above the ground to allow it to regrow with younger, more productive wood to produce more leaves and flowers throughout the whole plant. Rejuvenation pruning should be done just after flowering or in the fall for best health of the plant.

13. The last caller of the day wants to know about planting and growing blueberries and currants in Nebraska. He has pots he wants to plant them in to plant the pot into the ground. Is that necessary? What type of soil should be used?

A. Blueberries are not the best option for Nebraska soils. They must live in highly acidic soils, which we do not have. If determined to grow blueberries in Nebraska, it is best to grow them in a pot in the ground that can be brought up every year to amend the soil with acidic fertilizer or peat moss. Serviceberries may be a better choice to blueberries for Nebraska. Serviceberry is a native plant so it will grow in our natural soils with a lot less care and they have more antioxidants than blueberries do. There are also some newer varieties that have berries larger than blueberries. Currants will grow just fine in our natural soils and need no ammendments.

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Hot Weather and Plants

Drought in a lawn

Drought lawn photo from John Fech, Nebraska Extension Educator in Douglas/Sarpy Counties.

It’s hard to say what normal Nebraska weather is. However, this year has been particularly difficult for our plants. The quick change from cool to hot has caused some lasting effects on our plants. Some of the common problems we have been seeing this year include: leaf scorch, drought problems, and poor pollination.

Leaf Scorch

Leaf scorch can happen on the leaves of our trees, vegetable plants, and other garden plants. Leaf scorch causes the tips of leaves of many plants to turn brown and crispy. The abrupt change in our environment from cold to hot and humid left even the most well-adapted plants struggling to stay green. Even plants that are not in full sun will be affected from the high temperatures, such as hostas that are planted in shade.

When the plant is unable to take up enough water, the leaf tissue that is farthest from the major veins will dehydrate first causing leaf margins to scorch first. Leaf scorch is not necessarily caused from lack of water, it is because the plants cannot take in enough water to compensate for what is being lost through transpiration. The moisture may be present around the roots, it just is not entering the plant as fast as it is leaving it.

Do not automatically go out an water the plants that are showing scorch. Watering may be necessary, but don’t overwater. Ensure that the plants have mulch around them and check the soil moisture before watering.

Dry Conditions

In these dry conditions we have faced through most of the growing season, it is important to remember to water your plants. But, it is always a good idea to check soil moisture before watering to help reduce the problems with overwatering. Most of our plants need about 1 inch of water per week, if they don’t receive that from precipitation, they need it from irrigation. If a screwdriver or dowel pushes into the ground easily moisture is sufficient around the plant. For trees the screwdriver should go down 12-18 inches, for perennials it should go down 6-8 inches and for turf and vegetables it should go down 4-6 inches.

Poor Pollination

The heat we are facing is also causing some slight problems with poor pollination and there are problems we could face later as our fruits begin to develop, abnormally. In this heat there is a condition called blossom drop that can occur. It is when the flowers abort and fall from the plant rather than developing into a fruit. This can also be due to drought conditions, which we are also facing. When temperatures reach 93 degrees F, pollen becomes sterilized, so even if they get pollinated, they are not fertilized and fruits will not develop.

The heat and drought we have been dealing with can also cause small fruit development and sunscald. Sunscald happens in high temperatures when our fruits develop without leaf cover. Don’t prune tomatoes too heavily or it can leave your fruits open to damage from sunscald.

We could also have problems with bitter tasting cucumbers this year. Cucumbers produce a chemical called cucurbitacin, which is bitter in flavor. Most cucumbers that we eat now have low amounts of this chemical, but they can produce more due to environmental stress. Uneven watering, drought issues, and high temperatures can all lead to the build-up of cucurbitacin. It is likely this year we may have a problem with that, and there is no way to fix it. Just be sure to try out your cucumbers while you are cutting them up for your recipes.

The leaf scorch information for this article came from Kathleen Cue, Dodge County Extension Educator.

Yard and Garden: June 15, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for June 15, 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: Jim Kalisch, Insect Diagnostician for UNL Extension

1.The first caller of the show wants to know how to attract more fireflies to his yard?

A. Fireflies like moist environments. So a location of higher shade that is kept moist with dense plantings will attract them to your landscape. Also, just keeping the lawn watered will help.

lonestar tick, lifestages, J. Kalisch

This photo from Jim Kalisch, UNL Entomology, shows the lifestages of the Lone star tick

2. This year has high populations of ticks found in nature. Many ticks around this area have been identified by Jim Kalisch as being the Lonestar tick. Is this species of tick increasing in population in Nebraska?

A. Lonestar tick nymphs are being found often now. They have been found in the southeast portion of Nebraska. The range for this tick has spread north over the past decade or 2 to include the southeast corner of Nebraska. Prior to this, the Lonestar tick was found further south of Nebraska. This tick is significant for health reasons because it spreads many diseases including Southern Tick Associated Rash Illness (STARI), rabbit fever and erlichiosis. It also can causes a food allergy to red meat. Because of this, it is always good to remember to use insect repellent sprays and check yourself for ticks when coming inside from outdoor activities.

3. A caller has a blue spruce that was planted from a container last spring at 3.5 feet tall. Now it is turning brown on top and the branches are getting a shepherd’s crook at the end of the branches. What is causing this and can the tree be saved?

A. This is likely a fungal disease called sirococcus shoot blight. The best time to spray the trees is in May with additional sprays every 3-4 weeks as rain occurs.  It is a little late for the spraying of this tree, but it would still be beneficial to spray the tree to reduce the spread. Using a liquid copper fungicide would be best. Next spring, spray the trees when the shoots are 1/2 to 2 inches in length.

Squash bug-NH-pic monkey4. An email question came through asking how to get rid of pumpkin bugs in the garden this year, he faces them every year?

A. From his description, these are likely squash bugs. They are common pests in pumpkins, as well as in cucumbers, squash, zucchini, and melons. If these bugs are in pumpkins that are for ornamental use only, not for consumption, a systemic insecticide called acetamiprid can be used. Be careful if using in a garden with other edible garden plants, read the label for the PHI to tell you how long to wait from when you apply this product until you can harvest again. If these plants will be used for consumption, eight or bifenthrin would work for less PHI. Still pay attention to the PHI for harvest times.

5. This caller has oriental poppies in her garden that have faded now. They are planted in an area that is becoming overtaken by weeds. She would like to plant mums around the poppies to get a longer season of interest. How can she work the soil to plant the mums and kill the weeds, while not harming the poppies.

A. Tilling through the garden space may not be the best answer. If you till through weeds, it can sometimes cause more of a problem. Many weeds will propagate vegetatively, so new plants will form from each of the cut pieces of the main plants. Also, it would be difficult to till around poppies safely. I would recommend carefully using glyphosate on the weeds for better control, do not use any 2,4-D or Dicamba products this time of year due to problems with these chemicals turning into gas and moving to non-target plants. Spot spraying the weeds or painting the chemical on the leaves would get more of a kill for the weeds and the glyphosate product will not turn into a gas and it deactivates as it hits the soil. Finally, just go in and just dig holes where the new mums will be planted.

6. A caller wants to know when the best time is to move tiger eye sumac?

A. Fall would be fine to move this sumac, such as in September.

This caller also has a 5-year-old peach tree that has borers. How can the borers be controlled?

A. For borer control, it is best to treat the base of the tree and the branch junctions with bifenthrin. This chemical will have to be reapplied a few times through the growing season to help with the lesser peach tree borer and the peach tree borer which emerge at different times of the year. Applications should be made in June and again in July and August for best control.

7. This caller has a 2-year-old black raspberry. The new growth is curling and turning black, it seems to be moving from the tip of the leaf inward. What would cause this?

A. This could be from a scorch issue. Make sure that the plants are getting enough water, but check before just watering more. Often when we get scorch we automatically go to overwatering which can also be quite detrimental to the plant. For more information on scorch and how to deal with it, visit the Gro Big Red Blog Post on Scorch from Kathleen Cue.

8. A caller emailed pictures of his fir trees that are having some issues. One, was planted about 6 years ago and the bottom few branches have turned brown. He watered through the winter but has not yet this spring. The other fir was replanted about 4 years ago and the top is green, but the bottom half is sparse. What can be done for these trees?

A. The bottom branches of this tree could be just dying from shade or from a needle drop issue. That branch or 2 can be removed and the tree should be fine. It would be best to water this tree. Put the sprinkler in the root zone of this tree weekly for an hour or so to help it. As for the smaller tree, it is not going to make it. The lower portion is quite bare and it will be very difficult for the tree to come back from that.

9. What do you do about sandburs in a lawn?

A. Crabgrass preemergent herbicides should be used earlier in the season to control sandburs before they grow. Sandburs are a summer annual weed just like crabgrass. For post-emergent control, quinclorac products will work best. If it is in a driveway or other non-plant area, roundup 365 might be fairly effective.

10. A caller has a birch tree that needs a large branch removed, when is the best time for this? They also have a pear tree that needs some pruning, when is the time to do this? And when can they prune a mock orange bush?

A. New research is showing the timing for pruning has changed from what was previously recommended. We now recommend pruning in the late spring to early summer, so that would be right now for both the birch and the pear tree. It is better to wait until a little later in the spring to prune birch trees to avoid problems with heavy sap flow. The concern with this is that it was stated that a large limb needed to be removed, which can be quite harmful to the tree. Don’t remove a limb that is more than 1/2 the diameter of the trunk and do not remove more than 1/4 of the tree in one growing season. Removing a large limb leaves a large wound that the tree is not able to seal up. If the wound doesn’t get sealed, then decay can begin to move through the tree which can lead to the death of the tree in many years. In addition, removing more than 1/4 of the canopy in one season will remove a great deal of the photosynthetic area from the tree, which can harm the growth and development of the tree. The mock orange bush should be pruned within a few weeks after blooming for the year because it is a spring blooming shrub.

11. The last caller of the day wanted to know about pruning tomatoes and how to do it?

A. Tomatoes can be pruned if desired, but it is not necessary. If desired, only prune on indeterminate tomatoes, avoid pruning determinate tomatoes. Determinate tomatoes already will only grow to a certain size and produce a certain amount of tomatoes so they do not need to be pruned. Pruning tomatoes can decrease the amount of tomatoes produced and increase the size of the tomatoes and it can help increase air flow to reduce diseases. It will also help keep your tomatoes off the ground. When the plants are young, remove some of the branches. In some locations, 2 or more leaves will start to develop from one node, remove all but one. For more information on pruning tomatoes, here is a guide from Minnesota Extension.

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.

2016-04-02 10.11.52

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.

Brown Lawns caused by a leaf blight

Ascochyta, 6-2018

Symptoms from Ascochyta Leaf Blight

This year has been difficult for our lawns. Since our cold April, our temperatures skyrocketed and we haven’t had many rain events throughout this spring and early summer. This has been causing our lawns to look a little ragged and brown.

Ascochyta

Many cool season lawns throughout Eastern Nebraska have begun to look brown due to Ascochyta leaf blight, a widespread disease found throughout the early part of summer this year. Mowing during the hot Memorial Day weekend seemed to have worsened the symptoms of this disease.

Symptoms

Ascochyta close up, 6-2018

A close-up of the blades of turf infected by Ascochyta

Ascochyta is a diseased that is stress-induced and often shows up in the early summer when the weather shifts from cold and wet to hot and very dry. Ascochyta is a dieback from the tip of the leaf blades of cool season turf. Red-brown spots can also appear lower down on the affected blades. You might also notice a dark brown/black band between green growth and the brown tip of the blade. After the initial disease moves through, a general brown appearance will show up in the lawn, often following lawn mower tire patterns. Mowing worsened the symptoms of this disease, not by spreading it, but by the physical traffic of the equipment  to weaken the turf. This allowed for ease of the fungus to attack the lawn.

Ascochyta affects just the turf blades of the plant, not the roots or crown of the plants. The crown is the growing point of the turf. Because it doesn’t affect the roots and crown of the plant, it is then able to grow out of the disease. Mowing the lawn will remove the infested areas of the plant which will lead to regrowth and regreening of the lawn over time.

Management

There are a few types of fungicides labeled for use on ascochyta, however, research at UNL shows poor results with many different classes of fungicides on this disease. The best management for Ascochyta would be to reduce stress and manage the lawn properly. Provide adequate moisture for the lawn. Remember it is best to provide 1-1.5 inches of water per week to the lawn. If that isn’t provided through rainfall, irrigate two to three times per week with 1/3-1/2 an inch each time to keep the lawn healthy. Also, ensure that your lawn mower blades are sharp to avoid tattering the leaves which can leave more of an opening for diseases to move into grass plants. Finally, early June is a great time for a slow-release fertilizer to help slowly feed your lawn through the summer months and keep it healthy.

For More Information

The information for this news article on Ascochyta came from the UNL Turfgrass Team of Bill Kreuser and Roch Gaussoin. This information came through a Turf iNfo update. You can sign up to be on their listserv to receive these updates automatically as they come out by going to the Nebraska Turfgrass Website and scrolling down to click on the ‘SIGN UP FOR TURF INFO’ tab at the bottom of their page.

 

Yard and Garden: June 1, 2018

Y&G Blog Photo, 2018

This is the Q&A for the Yard and Garden show for June 1, 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: George Pinkerton, Director of Landscape Maintenance for Downtown Lincoln

1.The first caller of the show wants to know how to control grassy weeds in peonies and in asparagus?

A. In the peony plants, you can spray Grass-b-Gon or another product containing fluazifop-p-butyl to kill perennial and annual grassy weeds. However, this product cannot be used in asparagus. For weed management in asparagus, it is best to use mulch through the season to keep the weeds down. Roundup, or glyphosate, can be sprayed over top of the asparagus in the beginning of the season before the asparagus begins to grow, after harvest once all the stalks have been cut off below the ground level, and at the end of the season after removing the ferns and no green of the asparagus is showing above ground. Preen that is labeled for use in asparagus can be used throughout the season as well to stop the germination of new, annual weeds.

2. This caller has ants on their potatoes and radish with a great deal of damage. What can be done to stop the ants from damaging these plants more?

A. It is likely that the problem is not due to the ants, they are likely there as a secondary issue and they are not eating the potatoes and radish. Grubs will feed on the tubers and other underground structures. They do not typically affect tomato roots or the roots of the other above-ground growing plants. There are no products labeled for grub control in a home vegetable garden. If the grubs are becoming a problem, move the garden next year and treat the area without the vegetables on that area for a year. Treat for grubs in the lawn around the garden to help reduce the population.

3. A caller has had poor pollination in cucumbers in past years. What can he do this year to ensure he has better cucumber production?

A. If there aren’t many bees or butterflies around the garden, it could be low pollination. Try to attract pollinators through additional pollinator garden areas. You can also hand-pollinate these plants with a cotton swab, touching many flowers throughout the plant with the same cotton swab to transfer the pollen throughout.

4. This caller purchased burning bushes in containers and then left for 4 days before getting them planted. Now, the leaves are brown and crispy, are these plants dead or will they pull through?

A. If branches are brittle and break rather than bend, they are likely dead and will not regrow from that. In the late May time frame, it is going to be difficult to keep a newly planted shrub watered well enough in this heat and drought, this will be even more difficult if the plant is not placed into the ground right away. Containerized plants would need to be watered at least once a day now that it is so hot.

5. A caller planted 2 fruit trees and a red maple that they received through a mail-order service. The fruit trees are doing fine, but the maple has not leafed out and is not growing well at all. What happened? Will the tree come through?

A. Sometimes during transportation, bare root trees will dry out and they are not able to recover from that. It is best to purchase your plants locally to ensure this does not happen.

Carpenter Bee, J. Kalisch

Carpenter Bee Photo from Jim Kalisch, UNL Entomologist

6. How do you control carpenter bees?

A. Carpenter bees are a good pollinator insect and will not sting you. If they are doing damage to the structure of a building, you can fill the holes with some caulk or putty. If you would like to, you can inject sevin dust into the holes before sealing the holes to kill the bees. For more information here is a guide from Lancaster County Extension on Carpenter Bees.

7. This caller has Siberian elms growing within a well-established windbreak that are dropping yellow leaves. What is wrong with the trees?

A. It is likely that the trees turning yellow are hackberry trees growing in the windbreak rather than the elm trees. Hackberry trees have recently been dropping leaves like they do in the fall. They tend to do this in the late spring if the weather becomes unfavorable to their growth. They will drop their leaves and then push new regrowth. This is likely due to the quick change to hot/dry this summer.

8. A caller just planted rose bushes and oak leaf hydrangea plants in full sun with a rock mulch. Now the roses have holes in the leaves and the hydrangea plants are getting rush spots. What is wrong with these plants?

A. After a picture was emailed, it was determined that the roses had rose slug damage. Rose slugs are actually the immature form of sawflies that feed on roses this time of year causing brown spots in the leaves and holes. Rose slugs resemble a caterpillar that is translucent green with a brown head and they are found on the underside of the leaf. They are not very detrimental and do not need to be controlled. They are a short-term problem. Also, it is difficult to control sawfly larvae and not harm pollinators in the flowers of the rose. The hydrangeas are exhibiting problems with heat due to being planted in full sun with a rock mulch. Make sure to keep them well-watered to avoid more problems.

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Creeping Charlie in a lawn

9. This caller has a mint smelling weed growing in his yard. What is it and how do you manage it?

A. This would be Creeping Charlie, also called ground ivy. This weed can be difficult to control, but it is best managed in the fall. Many broadleaf herbicides will work for creeping Charlie, including 2,4-D, trimec, tenacity, or triclopyr. It is best to apply one of these chemicals 2 or 3 times in the fall. One application can be made around September 15th with a second application around October 15th. It will take multiple years of this management plan to fully rid the yard of ground ivy.

10. A caller has zucchini leaves that are crisp and curled up rather than smooth like normal growth. What is wrong with the plant?

A. After discussion with the caller, it was determined that she should spread her watering out more. Our vegetable gardens need about 1 inch of water per week, but this should be spread out over 2 or 3 times per week if rain is not providing that water. She also sent a photo to Nicole, where it was determined that this might be due to herbicide drift from a broadleaf herbicide applied nearby. In the heat and humidity we are dealing with currently, it is best to not use broadleaf herbicides anymore now until the fall of this year to avoid volatilization of the chemicals where they turn into a gas and move around to non-target plants.

11. How much water does a lawn need? How do you know how much water you are applying? Should you water in the afternoon to cool the grass off or is that a myth?

A. A lawn need 1-1.5 inches of water per week. If you are not getting that naturally, it is best to apply 1/3-1/2 of an inch 3 times per week to keep the lawn healthy. You can do an audit of your system to know how much you are applying each time you water. Simply place tuna cans or some type of catch device throughout the lawn to catch the irrigation as it runs to determine how much is being applied each time. As for syringing the lawn, no it doesn’t really help the lawn cool off. Lawns transpire as a natural way to cool themselves, and syringing only cools the lawn a few degrees for a few minutes. For more information on syringing, here is a good Turf iNfo article from Bill Kreuser at the UNL Turfgrass Department.

12. This caller has something that is digging large holes in the yard. What would be causing this and how can the damage be controlled?

A. This could be due to a skunk digging up the grass looking for white grubs. Treat the lawn for grubs in the middle to late part of June to help reduce the attractant for the skunks. For more on skunks and how to control them, here is a guide from UNL Wildlife.

13. A caller is looking for a good plant to use to grow up a windmill. Would a vining hydrangea be a good choice to grow on the windmill that is in full sun?

A. No, hydrangea plants don’t grow well in full sun. Honeysuckle would be a good choice for this location. If you can keep the roots a bit shaded, clematis would be another great choice.

14. The final caller of the day wanted to know how long tulips can live?

A. Some of the newer varieties may not live as long as some of the old types. However most will grow for many years.