Yard and Garden: July 7, 2017

Yard & Garden for blog, 2017

This is the Q&A for the Yard and Garden show for July 7, 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: Bob Henrickson, Assistant Director of the Nebraska Statewide Arboretum

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 has 10 lilacs growing in a lawn which are now getting a gray film on the leaves. What is causing this problem?

A. This is due to powdery mildew. This is a common problem on lilacs. Lilacs often get this disease if they are planted too closely together reducing air flow or if they are planted in heavy shade. If these plants are not growing in either of these environments, it is likely due to the wet spring we saw this year. Fortunately, this disease is not very damaging to the plants and there is no need to treat for it.

2. A caller has many American elm trees growing in his pasture that seem to suddenly be dying this year after the leaves turn brown and curl up on the branches.

A. Unfortunately, this is likely due to Dutch Elm Disease, which is still present and active in Nebraska. Many of our trees can grow for a few years and then the trees get large enough and conditions become conducive, that it shows up and kills the trees fairly quickly. The only management strategy is to remove and destroy the infected trees to reduce the spread to other trees.

chicory, Joseph M Ditomaso, Univ of CA-Davis, bugwood

Photo of Chicory from Joseph M DiTomaso, University of California-Davis, Bugwood.org

3. What are the blue flowers blooming along the roadside now and can the seed be purchased somewhere?

A. That is chicory, a non-native plant often used in roadside mixes. The seed can be found in some roadside mixes or at local seed sources.

4. A caller has a sunset maple with leaves that are curling and falling off the tree. What could be wrong with the tree?

A. This could be due to herbicide drift. Trees stressed by herbicide drift will often lose their leaves and push new growth. As long as they are producing new leaves that are not curled, the tree will likely be fine. However, many years of damage from herbicide drift can cause more stress and even possibly death.

5. This caller has voles in their yard. How can these be controlled?

A. Snap mouse traps can be placed in the runs perpendicular to the runs. These traps will catch and kill the mice. Here is a guide on vole control

6. A caller has a copper-colored beetle in her elm trees that are causing holes in the leaves. What would this be and how can they be controlled?

A. This could be a Japanese Beetle, an invasive insect from Japan. It is a green beetle with copper-colored wings. These beetles need to be controlled as they can do a lot of damage quickly. They chew on the leaves causing a skeletonization of the leaves as they leave behind the leaf veins. They can be treated with a insecticide containing imidacloprid.

7. A caller has a grass that grows in her lawn. The grass grows in a large circle about the size of a dinner plate and tends to turn brown in any kind of drought when the rest of the lawn does fine, but thrives in higher moisture content. What would this be and how can she make her lawn look more uniform?

A. This could be a cool season weedy grass species. They are often found in our lawns growing in a large circle. I would recommend spot spraying the areas of this different type of grass and then reseeding. This would be best done this fall. Be sure to spray the spot while it is still green and actively growing and use a product such as glyphosate. Overseed the areas in September.

8. This caller has hollyhocks with brown spots on the leaves. What could this be from?

A. This is likely due to hollyhock rust, a common fungus of hollyhocks. Remove the leaves as they develop the disease and destroy the leaves and plant parts removed in the fall cleanup. Fungicides can be used if necessary, such as a liquid copper fungicide.

9. A caller has peach trees that have developed some insects in the peaches making them unedible. What can be done about that?

A. There are a lot of different insects that feed on the fruits of peaches. The oriental fruit moth is one. For any fruit tree, either deal with some insect and disease damages throughout the years or keep your trees on a spray program. Spray every 10-14 days throughout the growing season with an Orchard fruit tree spray that contains two insecticides and a fungicide. Avoid spraying during full bloom. For more information, visit food.unl.edu/local-food-production

10. This caller has a sycamore that has shed some leaves and is now shedding bark. What is wrong with the tree?

A. The shedding bark could be normal. Sycamore trees have an exfoliating bark that is normal to give it the camouflage bark appearance. It may have been hit earlier this spring with anthracnose causing the leaves to drop. Anthracnose is a minor, but common, disease of sycamore trees. It is more prevalent in wet weather, such as this spring. There is no control for it, but the tree should be fine.

11. A caller has been trying to seed grass where a septic tank was and can’t get it to grow. What is wrong?

A. At this point in the year, it would be best to wait until fall to plant grass seed due to the heat, humidity, and lack of rain. However, if you have been trying in the spring and fall and can’t get it to grow, I would recommend getting a soil test done of the soil where this problem is occurring. This will help tell if the soil has other problems because of the septic tank or what was put back into the hole. It was also determined that this is an area around a large tree with a great deal of shade, if the area is too shady for grass, try a groundcover or a carex species that will grow better in more shade.

12. When is the best time to spray for bagworms?

A. Now would be a good time since the bags have emerged. 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.

13. A caller has a Norway Spruce that is 8 feet tall. It has been drying up since this spring and looks like it is dying. The tree has been planted here for 5-6 years and is watering slowly every 2 weeks since the trees were planted. What is causing it to die?

A. This could be due to overwatering. The roots of the trees need to breathe in between waterings. If the caller is filling a moat around the trees with water every 2 weeks for this many years, it would be excessive.

14. The final caller of the day wondered if the yard could be sprayed to help with chiggers? He also wondered when the time was to use sedgehammer on the lawn?

A. Nothing can be sprayed on the lawn to entirely help with chiggers. The best defense against chiggers would be to use insect repellent that contains DEET and to wear light colored clothing. Sedgehammer is best used before June 21st or the longest day of the year to help reduce the populations of nutsedge for next year. However, it can still be used this late in the year to kill what is in the lawn this year.

Deer, Rabbits, Voles, Oh My!!

With November here, we can expect cooler temperatures and more interactions with wildlife. Often times these interactions are with the deer, rabbits, and voles chewing on our plants. These pests can cause a great deal of damage and can be controlled in our landscapes to protect our plants over the winter months.

My beautiful picture

Deer can really be a nuisance to plants in all seasons of the year. They can chew off the ends of small twigs and bucks can rub their antlers on smaller trees, injuring the bark. I get a lot of calls from people who want to know what the silver bullet is to reduce the amount of damage that deer do to our vegetable gardens and trees and shrubs each year. The sad truth is that there is no real cure for deer damage to our plants. Exclusion is going to have the biggest impact on deer damage to our plants

Deer Rub on Tree, Photo from USDA Forest Service - North Central Research Station , USDA Forest Service, Bugwood.org

Deer Rub on Tree, Photo from USDA Forest Service – North Central Research Station , USDA Forest Service, Bugwood.org

Excluding deer from our plants is sometimes a difficult task, but it can be done, in smaller areas, like around acreages. There are fences that can be utilized but they need to be at least 8 feet tall. Another type of fence that has proven quite effective is an electric fence that has small squares of aluminum foil coated with peanut butter, placed sporadically on the fence. This technique is used to eventually train the deer to stay away from the fence, even if the electricity is not turned on. This electric fence technique should not be used in an area where a child or a pet can get to the fence so that they do not get electrocuted. The commercial spray repellants available for deer are not effective.

Rabbit Protection Fence, Photo from Lancaster County Extension

Rabbit Protection Fence, Photo from Lancaster County Extension

Rabbits can also be quite a problem in areas where deer are a problem. Rabbits will chew on small plants. In the summer they chew many of our plants off at ground level, and in the winter months they gnaw on the thin bark of young trees to feed on the green inner bark areas. Rabbits can be excluded by surrounding a garden or landscape area with a low fence, at least 2 feet tall. Cylinders can be placed around young trees to reduce damage during the winter. Habitat modification is another good way to control rabbits, remove brush piles, debris, and other cover that rabbits prefer to live in during the winter. As with deer, the commercial spray repellants available for rabbits are not effective.

Vole damage, NebGuide

Vole Damage Photo from NebGuide “Controlling Vole Damage” by S. Vantassel, S. Hygnstrom, D. Ferraro

Voles are another species of wildlife that can do a great deal of damage to our plants in the winter months. If we receive enough snow cover, voles may feed on trees and shrubs, they will also gnaw on tree bark and roots, and potentially kill plants. To help prevent this, keep tall grass and weeds removed from around the trunk of trees and avoid mulch layers deeper than three inches. Placing hardware cloth around tree trunks will prevent vole feeding.

Yard and Garden: May 8, 2015

Yard and Garden Green Logo

This is the Q&A for the Yard and Garden show for May 8, 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: Graham Herbst, Community Forester with the Nebraska Forest Service

1. This caller has pampas grass growing in her yard that last winter had problems with winterkill. What would be a good alternative ornamental grass she could plant?

A: Pampas grass had a lot of problems with winterkill last spring due to the dry, cold, windy winter conditions we faced in the winter of 2013-2014. Pampas grass is on the edge of its hardiness zone in Nebraska, but there are many other options for native grasses here. Maidenhair grass, or Miscanthus, is a great choice for a large native grass and it has many varieties to choose many different qualities. Big Bluestem and Little bluestem are great native choices, as well as switchgrass, sideoats grama, and many more. Ornamental grasses give us winter interest and habitat and food for wildlife during the winter months.

2. A caller had a sewer that was dug out and filled with soil. She then seeded new turfgrass on the area that has come up and is growing well. This spring the area sunk back down 6 inches. What can she do to level this area out?

A: You can remove the grass from that area, gathering 4-6 inches of soil and roots with it. Add soil to bring that back up to level with the surrounding lawn, and replace the grass piece back on top. Keep this grass well-watered until it becomes established, it will act like a piece of sod. The other option would be to back fill the location with soil and reseed the area with turf seed.

3. A caller has orange odd-looking structures hanging off of her cedar trees. What is this? Will it harm the tree?

Winter gall of Cedar-apple rust.

Winter gall of Cedar-apple rust.

A: These would be the galls from a disease called cedar-apple rust. This disease requires 2 hosts to complete its lifecycle, a cedar and an apple or something else in the Malus family such as a pear or crabapple. This disease overwinters on cedar trees as a hard, brown, odd-shaped structure on the branches and with spring rains they open up to look like orange, gelatinous, galls that are reminiscent of an orange octopus. This is when the spores are spreading to the apple trees. This disease causes no real damage to cedar trees, but on apple trees it causes lesions on the apples and leaf spots. Here is a NebGuide on Cedar-Apple Rust.

4. This caller has 3 apple trees and this winter one of them has not bloomed nor leafed out. Is the tree dead?

A: Check the tree for living tissue by scraping the bark off to expose green or brown tissue underneath. If it is green, it is still alive, if it is brown it is dead. Also check the branches for flexibility, if they bend they are still alive if the break they are dead. Give the tree a few more weeks to see if it comes out of it later this spring.

5. This caller has moles in their yard. How can they be controlled?

A: Moles can be controlled with traps. These traps will euthanize the mole in the hole to be left behind after control has been achieved. These have the best effect if the mound is pushed down 2-3 times prior to placing the trap in the hole, this will show if the tunnel is an active one before the trap is placed in it. Here is a guide from the Internet Center for Wildlife Damage Management on Mole Control.

6. This caller has voles in their yard. How can they be controlled?

A: Voles are controlled with snap traps that we typically use for mice. Place 2 traps in the run from the voles, or the area where the grass is damaged. Place the traps perpendicular to the runs and place them facing in different directions in the run. So, for a vole run that goes North to South, place one trap facing east and one facing west. Here is a guide from the Internet Center for Wildlife Damage Management on Vole Control.

7. This gentleman had used Scotts liquid turf builder on his lawn and it is not working to green up the lawn or to reduce the weeds found in his lawn. He also has a zoysiagrass lawn that is not growing as well in some portions of his lawn as it has in the past. What would be causing these problems and how can he improve these?

A: Broadleaf weeds are best controlled in the fall so it is best to apply a broadleaf weed killer, such as 2,4-D, 2 times in the fall, such as September 30 and October 15. Even in the spring, some control can be achieved, but they will require more than one application as they are tough weeds to kill. The zoysiagrass may have experienced some winterkill so it might be wise to take plugs from the area of the lawn where it is growing well and move them into areas of the lawn where it is not growing so well.

8. This caller has ash trees that are getting oval-shaped holes in them and ants on the trunk of the tree. Did the ants do this to the tree? How can it be managed?

A: These ants are probably carpenter ants. Carpenter ants do not harm your trees, they will just burrow into wood that has already begun to decay for some other reason. Carpenter ants on a tree do not require treatment. The holes are most likely due to native borers of the ash tree, such as red-headed ash tree borers or ash-lilac borer. These borers can be controlled with a trunk spray with chemicals such as sevin or eight or apply a soil drench with an imidacloprid product around the base of the trunk. This doesn’t sound like it is Emerald Ash Borer because the holes from EAB are D-shaped, not rounded or oval.

9. This caller has an ash tree and wants to know when he should treat it? He has heard that it takes up to 5 years for the systemic insecticides to move throughout the tree into the canopy, if this is true should he treat now.

A: Systemic insecticides take only a couple of weeks to move throughout the entire tree and they only last for 1 or 2 years depending on which chemical is used. It is best to wait until Emerald Ash Borer gets within 15 miles of the tree before treatment begins because treatments are costly, damaging to the tree, and not necessary until the borer gets closer. Trunk injections wound the tree and after repeated years of treatments it causes a great deal of stress to the tree, so there is no need to treat and harm the tree prior to when it is necessary.