Blackwelder column: Oakworm to blame for droppings

Published 12:00 am Thursday, August 25, 2011

SALISBURY — Cooperative Extension still receives a number of questions via phone and email despite the waning growing season. The recent rains have created some problems for homeowners.
This period is generally slower than most, but horticultural problems do occur. Below are a few questions that you may have pondered.
Q: From a woman who brought in a sample: I have large oak trees that are over my swimming pool and there are insect droppings everywhere. Is there anything I can do to prevent this?
A: Your problem is most likely orange striped oak caterpillars. These caterpillars appear in mid-August and early September and can literally strip a tree bare in just a few days. Since it is late summer, it will not cause any harm to the growth of the tree, but the droppings can be a nuisance. There is no practical control for the insects.
Q: My shrubs have grown a bit over the past few months. Can I prune them now?
A: Yes, light, judicious pruning can occur all during the year. However, avoid pruning spring flowering shrubs such as azaleas and rhododendron. If you prune them now you will eliminate many of your flowers. Prune those shrubs in the spring after bloom. Prune shrubs back hard such as holly, red tips or boxwood in the early spring to avoid winter damage. Maples should be pruned now while they have leaves to avoid excessive bleeding in the spring.
Q: From an email: I live in the western part of Rowan County and I have these small blue berries growing on small shrubs around my property. They are rather small berries and grow in bunches. Can you identify them for me?
A: The berries are most likely elderberries (Sambucus sp). The plants are native to Rowan County, growing on ditch banks and edges of fields. The blooms in early spring look much like a hydrangea. More information on elderberries can be found at
Q: Is it too late to kill Bermuda grass in my lawn?
A: No, but don’t wait too long. Cooler fall temperatures reduce the effectiveness of systemic herbicides like glyphosate (Roundup). Systemic herbicides are best for controlling Bermuda grass. Once the daytime high temperatures reach the 60s these herbicides become less effective. Bermuda grass grows best at 100 degrees. We may still have a few days that approach that temperature and allow the herbicide to work effectively.
Darrell Blackwelder is the County Extension Director with horticulture responsibilities with the North Carolina Cooperative Extension Service in Rowan County. Learn more about Cooperative Extension events and activities by calling 704-216-8970 or online at