Q. Are sow bugs good or bad?
A. Pillbugs and sowbugs are not insects, but small crustaceans that are closely related to crayfish. Pillbugs are sowbugs that can roll themselves into a ball for protection. They feed at night, and hide in damp, protected areas during the day.
Sowbugs often get blamed for damage they don't do because they are so often found around damaged plant material. They are important in the decomposition of decaying organic matter in the garden since their primary source of food is decaying leaves and fruits. They are often prevalent on fruits that have been previously damaged by other pests. Before you begin a program to control sowbugs, make sure that you are targeting the real problem.
Sowbugs will feed on fruits and vegetables like strawberries, melons and squash that lay directly on the ground. They can be deterred from feeding by using a coarse mulch that keeps the ground immediately under the fruits from staying damp. Trellising vine plants will reduce the number of decaying leaves on the ground. Elevating squash and melons will protect them from feeding by sowbugs.
Water early in the day to allow the surface of the soil or mulch to dry out before the sowbugs begin to feed. Remove any hiding places such as old boards or pots. Think about reducing the number of sowbugs rather than trying to eliminate them. Remember, they are part of the natural processes at work in your garden.
Q. I have a 6-foot-tall clematis that wilted over a few days. It has brown spots on the leaves. I watered it but it didn't come back.
A. Clematis is susceptible to a fungal disease that causes a leaf and stem spot. The disease starts on the leaves then extends down into the stems. These spots can become severe enough to girdle the stem and cut off the movement of water and nutrients necessary for plant growth. The damage often appears to happen quickly, although the disease has been present throughout the spring.
The fungal spores overwinter on the infected stems and leaves, so cleaning can be an important method of control. Prune out infected stems and rake up and remove all the leaves. Sulfur can be used to control the fungus, but should be used with care. It will burn leaves when applied during temperatures over 85 degrees. Carefully read and follow the directions on the label.
Q: The leaves of my big rhododendron are getting big, long oval rust-colored spots, but only on some of the leaves.
A: These sound like symptoms of heat/sun damage. Brown blotches such as you describe are usually worse on the south or southwest side of the plant and on leaves directly aligned with overhead sunlight.
Many summer problems of rhododendron result from lack of good cultural care. These plants require regular deep soaking in our dry summers. Be sure that it gets a deep watering at least twice a month if we don't have soaking rains (usually unlikely in July and August).
The careful watering will probably not prevent sun scorch but will keep the plant healthier and more able to replace damaged leaves. Some rhododendrons tolerate sun better than others; you may want to consider moving this plant to a more sheltered location or replacing it with a more sun-tolerant cultivar.
Many people think of rhododendrons as being the mascot plant of the maritime Pacific Northwest because they are so frequently planted here. Taking care of them during our summer dry spells is vital, as most of them are native to areas that get more summer rain than this area does.
Gardening runs Friday in Scene and Sunday in Home/Real Estate. It is prepared by Mary Robson, Area Horticulture Agent; Holly Kennell, Washington State University/King County Cooperative Extension agent, Susan Miller, integrated pest management specialist, and volunteer Master Gardeners.