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.

5-4-11 (2)

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.

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Yard and Garden: June 23, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for June 23, 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 Hosts: Mike Onnen, Manager for the Little Blue NRD & Donnie Engelhardt, Assistant Manager for the Little Blue NRD

If you enjoy reading my Q&A from the show each week, take my quick survey at: http://go.unl.edu/44qr and be entered to win a free plant book or some free UNL gifts.

1.The first caller of the day wanted to know if it was time to spray for bagworms yet this year and what to use for bagworms?

A. Yes, the bags have emerged. There is time for a couple of weeks yet to get them sprayed, just make sure you spray before the bags are 1 inch in length for best control. You can use any general insecticide for controlling bagworms such as sevin, eight, bifenthrin, tempo, or Bt can be used for a safer control method. Bt will not harm bees and other beneficial insects.

Bagworm4

Bagworm

2. A caller has 2 large oak trees that when he parks his truck underneath it gets sticky from the aphids in the tree. What can be done to manage these?

A. The aphids are producing honeydew as an excretion and they do feed on the oak trees, but often this is not that damaging to the tree. You can spray for the aphids in the tree with a general insecticide, but if you give it a little time predatory insects will come in and kill the aphids. If you spray, you will kill the predators as well as the aphids. It is often not necessary to spray for aphids in a tree.

3. This caller has lilies that have grown too thick in her one garden bed. When can she divide these to transplant some in a new location?

A. This could be done this fall or you can wait and thin the lilies in the spring as well, either would be fine. I would advise against transplanting and dividing plants this time of year because in the heat, the plants don’t have enough roots to get to more water to keep them cool.

4. A caller has a weeping willow that has many leaves turning yellow and the tree is thinning. What would be wrong with the tree and how can it be managed?

A. This tree is likely dealing with environmental stress. There are not spots on the leaves to indicate a disease or damage that would be from insects. After viewing the photos, it is determined it could be due to improper planting as it looks too deep with no root flare. There may be stem girdling roots that would not be evident for a few years after planting.

5. How do you control ground squirrels in your yard?

A. There is a great publication on Ground Squirrels from the Internet Center for Wildlife Damage Management which shows how to set a trap for ground squirrels.

6. A caller has Iris, yucca, and prickly pear cactus that are all getting many weeds growing in and around these plants. The weeds include both grasses and broadleaf weeds. How can the weeds be controlled without injuring the desired plants?

A. The grasses can be sprayed with Grass-B-Gon or another similar grass herbicide. Unfortunately, there isn’t a selective herbicide that will kill broadleaf weeds and not kill broadleaf desired plants. For the broadleaf weeds, the best defense is to hoe the weeds out and mulch the garden in the future to hold the weeds back.

7. This caller has a plum hedge that has holes in most of the leaves throughout the hedge. The holes form initially as a brown spot and then a hole appears. What would cause this?

A. This is likely due to herbicide drift. There is no control for that, but if it is minimal it shouldn’t impact the hedge too much. However, multiple years of herbicide drift to the same plants can start to stress and in some cases kill the plants.

8. A caller has onions that have formed a soft, brown spot on the onions when they were dug recently. What would cause this?

A. This is likely a rot issue that developed from a pathogen in the soil. It is always best practice to rotate the crops. Also, ensure that you properly cure your onions before storage.

9. How can you control sandburs?

A. Crabgrass control in the spring will work for sandburs as well as foxtail and crabgrass. All of these are annual grasses.

10. A caller has tried to plant roses in the same location for a couple of years now and it seems like they grow to about 18 inches, bloom, but then die over the winter months. The are planted in a garden with rock mulch, watered with a bucket of water as needed, and were pruned off in March. Why can’t the caller get the roses to live longer than one year?

A. This sounds like mostly environmental stress to these plants. Rock mulches are hot and absorb no water, switch to a wood chip mulch to cool the roots and hold moisture. Watering should be done with a soaker hose or other type of sprinkler system. When a bucket of water is poured over the plants as needed, the water fills up the top pores of the soil surface quickly and then spread out rather than down. A slow trickle on the plants for a while each week to wet the soil down to about 6-8 inches will be more beneficial. Pruning of roses is best done in the middle of April once growth has begun further to ensure healthy wood is not also removed with the dead wood too early in the spring. Add extra mulch around the plants in the winter months, up to 4-6 inches deep in the winter months, then spread the mulch out to 2-3 inches deep during the growing season. Extra mulch in the winter will help protect the plants from inconsistent temperatures in the winter.

11. This caller wants to know when to dig up garlic? He also wants to know if bleeding hearts can be cut back now?

A. Garlic should be harvested in July after 30-50% of the leaves have died back. Harvest during dry weather and leave the bulbs on the ground to dry for a week before storing. The flower stalks of bleeding hearts can be removed, but the leaves need to be left on the plants to build sugars for next years growth and flower production.

12. How can grasshoppers be controlled if they are in the flower garden?

A. Any general insecticide will work for grasshoppers in flower gardens. Sevin, eight, tempo, bifenthrin, and others will work for flowers. When treating grasshoppers, it is also important to treat the grassy areas of roadsides and ditches where grasshoppers are often found.

13. This caller has grass growing in his asparagus patch. How can the grass be controlled?

A. Hand pull and apply a mulch to the asparagus patch. The earlier you get the mulch applied in the season, the better the control will be. Also, after harvesting is complete, the asparagus can be snapped off below ground level and Roundup or another glyphosate product can be applied as long as there is no green asparagus above the ground.

 

Grasshoppers, J. Larson

The four main pest species of grasshopper in Neb. Top row two striped grasshopper adult, red legged grasshopper adult. Bottom row differential grasshopper adult, migratory grasshopper adult.

14. How can you control grasshoppers in the vegetable garden?

A. Sevin, eight, and bifenthrin are labeled for use in the vegetable garden. Also, remember to treat for grasshoppers in tall grasses along roadsides and ditches. Follow the PHI (pre-haravest interval) to know how many days after application necessary to wait to harvest the vegetables.

15. A caller wants to know when to transplant peach trees?

A. Fall or spring are both good times to transplant any trees.

16. The final caller of the day has a pond with moss or duckweed in it making it cloudy. What can be done to clean up the water?

A. Avast SRP is labeled for Duckweed and Copper sulfate can be used for Algae.