Q: I have four boxwood bushes in my front yard that are 10-12 years old. I have, in the past, trimmed them when needed and had no trouble until this year. They are dying and I don’t know why. What can I do to save them?
H. B. of Wood River
A: Your young leaves probably turned yellowish at first and wilted. Eventually braches of the plant die even though there is sufficient moisture. With all the rain we have experienced in the past few weeks, the soil does not drain well and favors the development of root diseases. If you cut off a branch closer to the soil level, check to see if the bark looks discolored. If so, peel back the bark at the bottom of the stem. There will be a distinct margin between white, healthy wood and dark, diseased wood. Then if you notice this condition, pull one of the plants up and look at the young roots to see if they have turned brown. Healthy roots are bright white in appearance. If they are brown, a soil-inhabiting fungus (Phytophthora cinnamoni) has entered the roots and will work its way up the plant, blocking the upward flow of water and nutrients.
There is no chemical control for this condition. But by lifting these plants and replacing the soil with fresh soil from a drained area, you may be able to save these plants, but it will be a slow recovery. You will need to replace as much soil as possible by making a hole larger than the area of the original roots. Also make the mound taller so that the upper roots will be higher than the original soil level so that the water will drain from the original hole. This will help reduce the chance of future root rot.
Q: I have several cedar trees on my property and I have noticed something growing on the branches which look like a purpled dimpled ball. Some of these are opening up and resembles an orange jelly fingers that just started this spring with warm rainy weather. What is this?
C. S. of Belleville
A: You are describing a disease of apple-cedar rust, a fungal disease (Gymnosporangium juniperi-virginianae) which one year infects American cedar trees and infects apple tree leaves the next year. As the “jelly fingers,” as you call them, begin to dry up, they will release spores to be carried by the wind and if these spores land on apple tree leaves they will infect the leaves and fruit and form orange spots. Then in August this disease will form spores to spread back to the junipers. This entire cycle may take 18-20 months to move back and forth depending upon the weather conditions
When you notice the round galls on the juniper, remove them as the galls will kill the rest of the branch below the galls. You can also spray the junipers with ferbam as the active ingredient in August to prevent new infections from the apple trees.
If you are thinking about planting cedar trees near apple trees, plant the Chinese juniper instead of the American juniper as the Chinese are resistant to this disease. Also locate your yearly wind patterns to also help prevent the spread of this disease.
Charles Giedeman is a local contributing writer. Send your gardening questions to Lifestyle Department, Belleville News-Democrat, P.O. Box 427, 120 S. Illinois St., Belleville, IL 62222-0427, or email them to firstname.lastname@example.org.
Things to do this week:
- Make cuttings of bleeding-heart for starters by lifting the plants and removing the little roots and breaking them into three-inch sections and plant in three-inches deep in rich compost soil.
- For low bushy growth of snapdragon, zinnia, and marigold, cut out the taller center stem.