Q. Two years ago, my fall-planted pansies were badly damaged by a fungal disease, so I planted a different variety last year. They had no disease problems. Are some pansies more susceptible to disease than others?
A. Pansies are susceptible to several fungal diseases, the most important of which is botrytis blight. Botrytis is a cool-weather disease that thrives in damp conditions; it is rarely a problem under warm, dry conditions. Two years ago, we had a number of cool, damp days in late fall that were ideal for the development of botrytis blight. However, last year we had a warm, dry fall. My guess is that the weather was a more important factor in your disease problems than the variety of pansy that you selected.
To prevent botrytis, it is important to keep the foliage dry. Avoid overhead watering and plant your pansies in an open area that has plenty of air circulation. If you must use an overhead sprinkler for watering, it is best to water in the morning, so that the foliage dries before sunset.
Q. Many of my perennials have suffered badly from the drought. They are not only dry, but also have been damaged by chewing insects. Should I cut back my plants to prevent more infestation?
A. This is a difficult question because we have so little experience in dealing with a drought of this extent. In a normal year, I would recommend cutting back some plants in late summer to encourage a flush of new growth for the fall. This is not so much for the health of the plant, but rather to green up the garden. However, I see little advantage to cutting back your plants this year and at this late date.
Cutting back your plants now will likely encourage new growth and put increased stress on the plants. Further, most insect damage for the year has already been done, so I do not think that you will prevent further damage by removing the remaining foliage. However, because many insects overwinter on plant leaves and stems, I would remove the foliage in late fall. The foliage should be composted or destroyed to prevent overwintering insects from infesting your garden next year.
Dennis Bishop is an urban horticulture educator for the Baltimore office of the Mary-land Cooperative Extension Services. If you have a gardening or pest problem, you can call the Home and Garden Information Center hot line (Monday through Friday, 8 a.m. to 1 p.m.) at 800-342-2507. You can also e-mail questions, order publications and diagnose plant problems by visiting the Web site, www.hgic.umd.edu.
1. Extra parsley, garlic, chives and thyme can be potted now and brought indoors for the winter.
2. It can be very difficult to pull weeds when the ground is dry. However, you can help control them by cutting them back. This will prevent them from producing more seeds.
3. Save the seeds from your favorite bean plants by letting them dry completely in the pod. They can be stored in glass containers.