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.

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Yard and Garden: July 1, 2016

Yard & Garden for blog

This is the Q&A for the Yard and Garden show for July 1, 2016. Yard and Garden Live is a call-in radio show I do on KUTT 99.5 FM from 10-11:30 am and it will run through August 5, 2016. It can also be found on kutt995.com for online listening. If you missed a show or just want to read through the questions, I have written them all in my blog and will continue to do so throughout the season.

Guest Host: Bob Henrickson, Assistant Director of the Nebraska Statewide Arboretum

1. The first caller of the day wants to use weed fabric and white rocks around the foundation of his house. Is this a good idea?

A. This can be done, but as horticulturists, Bob and I are always for more greenspace and less rocks. The weed fabric will work for a short time but often weeds will germinate through or on top of the fabric and it is hard to remove or change after the fabric is in. A good option would be to plant shrubs and perennials in there to help hide the foundation to the siding. Wood chip mulches will help with weed control around the plants.

2. A caller has a problem with ground squirrels in their lawn.

A. a trap can be built to control ground squirrels. The Internet Center for Wildlife Damage Management has a good guide for 13-lined ground squirrels.

3. A caller has bees in their sand play area. What can be done about it?

A. The best control for this would be to cover the sandbox so the bees cannot burrow into the sand to build their nest. If this can’t be done, you can sprinkle a little sevin in the holes where the bees go to nest. This is not the best option if you have kids playing in the sand because the chemical would not be safe for that. Otherwise, spraying the sandbox with water or soapy water will deter and possibly kill the bees.

4. This caller has a bald cypress tree that had lacebugs last spring. This year it hasn’t leafed out on the branches, most of the leaves are on the trunk. What can be done for this tree?

A. Removal and replacement. When a tree only leafs out on the trunk there is some reason that the flow of water and nutrients is not going through the whole tree. This could be due to borers or some type of root issue. Even with trees that are 8 years old, they could have had a root injury or been planted too deeply or had a stem girdling root that is now causing death of the tree. There is no cure for this at this point in the trees life.

5. A caller has a new lawn that they are trying to rejuvenate. What would the process be?

A. They are watering 2 times a week with a sprinkler for a couple of hours at a time, this should be sufficient. Stick with what you have been doing and don’t abruptly reduce it. Fertilize with the holidays: Arbor Day, Memorial Day, Labor Day, Halloween. So at this point don’t fertilize until the fall. Fertilizing in hot weather can cause more stress or leaf burn. For weed control, use crabgrass pre-emergent in the spring with the Arbor Day fertilization and use 2,4-D in the fall.

6. What to do when planting a tree that is badly rootbound?

A. It is hard to fix a tree when the roots are already rootbound. Once they begin to grow in a circular pattern, they will continue to do that for life, and damage doesn’t always show up until the tree is 10-15 years old. It is best to look at the roots before purchasing to choose a smaller tree with healthy roots. Also, when you get it home, remove the excess topsoil from the top of the rootball to ensure that it gets planted at the correct depth.

7. An email question came in to ask what to do for stump removal where they cut down and removed some shrubs?

A. Keep cutting the suckers off as they regrow and mulch the area if you just want to be rid of the plants. If you want to replant into the area, you will have to remove the stumps by digging them out or using a stump grinder to grind them out. Do not use Tordon in this area as it is against label regulations and it will not speed up the process and it can kill other desirable plants.

8. A caller has a firethorn plant with spidermites that they see on the plant every year and it causes them to loose many leaves each year. What can be done for them?

A. A strong stream of water will often work for spidermites. If the population is too high you will have to use insecticidal soaps. If this is an annual occurrence you may want to remove these shrubs and replace them with something that isn’t so problematic in this area.

9. What do you do for sandburs?

A. Sandburs are an annual grass, so crabgrass pre-emergent herbicides in the spring will help reduce the population by stopping germination. At this point in the year you can use a post-emergent grass herbicide such as Drive. Keep the area mowed to reduce the seed production for next year.

10. A caller has honeysuckle that is now invasive through his yard. What can be done to eliminate the honeysuckle plants? Also, is hickory a good tree for Nebraska? Why don’t we see hickory trees planted more?

A. Continual cutting of the honeysuckle will eventually kill it. You may want to try to dig up the plant to help reduce the problem. You can also treat the stump with roundup and/or 2,4-D. Use 2,4-D products in the spring or fall, it is now too hot to use this product without possible damage to desirable plants. Hickory is a great tree for Nebraska, it is just underutilized. Good hickory tree choices for Nebraska include Shagbark Hickory, Bitternut, and King Nut. Shagbark Hickory was the Great Plants of the Great Plains Tree of the Year Selection in 2011.

 

Japanese Beetle, 7-16 Acreage

Japanese Beetle adult on the left and immature on the right. Photos by Jim Kalisch, UNL Entomology.

11. A walk-in listener brought in a green beetle to be identified.

A. This is a Japanese Beetle. It is identified by the green metallic color, gold elytra, and white spots along the sides of the abdomen. This is an invasive insect from Japan that feeds on over 300 species of trees and shrubs, it favors roses and plants in the rose family. It will cause a skeletonization of the leaves as the adult feeds. As immatures they are a white grub that feeds on the roots of our turf. Management of white grubs in the turf will reduce the population. As adults, they can be controlled with general insecticides such as sevin, eight, bifenthrin, malation, or others. Don’t use insecticides on the flowers or flower buds to help with pollinator populations.

12. The final question of the day was from an email asking what chemicals do you use for bagworms?

A. Bagworms can be controlled with Bt, spinosad, sevin, eight, malathion, or tempo. The treatments need to be completed before the bags are smaller than 1/2 inch in length. You can also remove bags as they are seen and throw them into a bucket of soapy water to kill them without pesticides if you can reach them all.