This is the Q&A for the Yard and Garden show for July 17, 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: Steve Karloff, with Special Guest Jennifer Morris from the Nebraska Forest Service
1. A caller has a 35 year-old spruce tree that has needles that are turning pink, brown starting at the bottom of the tree on the east side. What could be causing this?
A: This sounds like needle cast disease, a fungal disease, that is common in blue spruces this year due to the rains in the spring. The treatment period for this was in the spring prior to development of the disease. It should not kill the tree. Make sure that the tree is properly cared for with 1 inch of watering per week, applied slowly, and a mulch ring of 2-3 inches deep.
2. A gentleman has cucumbers that are developing improperly. They are large at one end and very skinny at the blossom end of the fruit. What would be the issue with this odd developed fruit?
A: This could be due to environmental conditions. Dry conditions, which we have seen since the rain quit in early June, could lead to poor fruit development. It can also be due to poor pollination. Avoid use of insecticides if pollinator insects such as bees are present around the fruit.
3. A gentleman brought in some metallic green beetles that are very large. What are they?
A. These are green June beetles. They are not damaging to our plants and therefore require no management tactics.
4. A caller has a shady area on the North side of the house. What would be a good groundcover for this area?
A: Holly, purple leaf wintercreeper, vinca, lily of the valley, hostas, snowberry, coralberry, Bleeading hearts, or coral bells will all grow well in a shady environment on the North side of a house. Many of these will stay around 2 feet or shorter, but the snowberry and coralberry and holly will all get taller. A good mixture of shade plants will look nice around a home.
5. A caller has an oak tree that is well established. He is looking for a good groundcover to plant underneath that.
A: hostas, bleeding hearts, coral bells, vinca, and purple leaf wintercreeper will grow well under the shade of a large tree. Grape hyacinth can also be planted around the other plants for early spring color and fragrance with little impact to the landscape later in the season.
6. What are the tall blue flowers growing along the highway currently?
A: Chicory. This is a wildflower often used in roadside mixes or in native prairies. They have a sky blue flower and most of the leaves are located at the base of the plant rather than up along the taller flower stalks.
7. A gentleman has a windbreak of cedars that is dying. He sprayed 2,4-D underneath to kill the wild cucumber. The trees are 30-40 years old and they have bagworms but he has not treated. What can he do to keep the windbreak?
A: This could be due to bagworms. They are heavy this year and right now is a good time to spray with many general insecticides including sevin, eight, malathion, Bt, or Tempo. This could also be a side-effect of the 2,4-D that may have moved into the root zone more quickly with the rain events this year.
8. A caller wanted to know what the best recommendation for mosquito control prior to a get-together would be?
A: Mosquitoes can be controlled for a few days by using a hose-end sprayer with permethrin or bifenthrin which have a longer residual than some other insecticides. These sprays need to focus on the shrubs and trees and tall grasses around the yard where the gathering will occur and they should only be done 2-3 days prior to the gathering. Aerosol foggers that contain pyrethrins can be used shortly before the party begins to help reduce mosquito populations as well. For the time of the gathering, tiki torches and insect repellents containing DEET will help reduce additional mosquitoes.
9. A gentleman brought in a pear leaf with orange spots on the leaves. What would be causing this?
A: This is due to a rust disease, Cedar-Hawthorn Rust. It is very common this year due to the wet spring. The timing for management is in the spring, May and June. There is no need to control it at this point in the season. See this NebGuide on Cedar-apple rust and related rusts of apples and ornamentals.
10. A caller has a maple that is 10-12 years old with leaves that are wilting, turning brown, and falling off the tree. What could be the cause of this?
A: Look for green tissue under the bark on the branches. This could be due to a high flush of growth in the spring that put on too many leaves for the tree to maintain now that the weather has dried up and gotten hot.
11. The same caller wondered if there was a control method for pine wilt?
A: No, the best control would be to remove and destroy the tree as soon as possible after the disease is noticed in the landscape to reduce the spread of the disease to other trees.