By Darrell Blackwelder
With above average temperatures approaching, many will be concerned about keeping their plants, trees and shrubs irrigated. When temperatures rise above 90 degrees, plants are going to wilt. Hydrangeas, rhododendron, tomato plants and bedding plants will look as though they need water.
Don’t overwater wilted plants. A good rule of thumb is to wait until early morning to determine if plants need hydration. If wilted in the morning then irrigate; if not, it may just be the heat.
Below are a few questions posed this week that may be of interest as many choose to work outside during the Memorial Day weekend.
Q: I’ve been working outside in my yard and I think I may have gotten infected with poison oak. Are poison oak and ivy leafed out yet? How can I control them?
A: Poison oak is now fully leafed. However, the sap from a deciduous or even a dead vine is still potent. Be careful when you cut stems and vines. Roundup (glyphosate) or a brush killer will eliminate the noxious weed.
Q: Is it too late for me to plant roses and other shrubs?
A: No, you can plant shrubs that are potted almost year round. Make sure to keep them mulched and irrigated during dry weather.
Q: I have a crape myrtle with white fungus like material on the leaves. What is this and how do I control the fungus.
A: Powdery mildew is a common problem on many crape myrtle cultivars. You can control the disease with fungicidal sprays if practical. This disease occurs during cool, damp weather. It will subside as the weather gets warmer and dryer. Also, there are powdery mildew-resistant crape myrtle varieties now on the market. Go to http://www.ces.ncsu.edu/depts/pp/notes/Ornamental/odin004/odin004.htm for more complete information on powdery mildew on shade trees and ornamentals.
Q: I have planted a new apple tree and it is growing very well. However, I noticed some orange spots on the leaves. Can you tell me what these are and how I may control them? Will it kill the tree?
A: Your tree most likely has cedar-apple rust. It is a fungus disease on both apple and cedar trees. The disease can be a problem if planted near cedar trees. Some cultivars are resistant. Sprays may help, but the disease usually does not kill the tree. Go to http://www.ces.ncsu.edu/depts/pp/notes/Fruit/fdin002/fdin002.htm for more complete information on fruit tree diseases, including cedar apple rust.
Darrell Blackwelder is the County Extension Director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County.