|Yard and Garden: Trees|
|News Releases - Environment, Weather & Nature|
|Written by Joy Venhorst|
|Wednesday, 22 June 2011 15:27|
My crabapple has begun to drop some of its leaves. Why?
Apple scab appears as velvety, olive-green to black spots on the crabapple leaves. Heavily infected leaves turn yellow and fall from the tree. Highly susceptible crabapple varieties may lose a large percentage of their leaves by mid-summer. Fortunately, apple scab does not kill affected trees. The damage is mainly aesthetic.
Apple scab can be prevented by applying fungicides from bud break through mid-June. For most home gardeners, however, controlling apple scab with fungicides is not practical. Sanitation also plays a role in controlling apple scab. Raking and destroying the leaves as soon as they fall should help reduce the severity of the infection next season. However, the best way to prevent apple scab is to plant scab-resistant crabapple varieties.
Why are the leaves on my pin oak yellow-green?
Correcting an iron chlorosis problem is difficult. Applying additional iron to the soil usually doesn’t help. The soil already contains sufficient amounts of iron. Adding more iron doesn’t overcome the problem. Lowering the soil pH to 6.0 to 6.5 would allow the roots of the pin oak to more readily absorb iron in the soil. Unfortunately, lowering the soil pH isextremely difficult, if not impossible. As a result, homeowner efforts to treat iron chlorosis are often unsuccessful.
One strategy that sometimes works is to have an arborist or other tree care professional inject an iron containing compound directly into the trunks of chlorotic pin oak trees. The effects of a trunk injection may last three or four years.
Why is my sycamore tree dropping its leaves?
Symptoms of anthracnose on sycamores include brown blotches on the leaves, death of young buds and shoots, and leaf drop. In cool, wet springs, affected sycamores may lose most of their initial foliage.
Fortunately, the sycamore trees will continue to produce additional leaves and shoots through early summer. Foliage that develops in late spring and early summer shouldn’t become infected as warmer, drier weather suppresses anthracnose. Most sycamores should have a good canopy of leaves by late June or early July.
Since anthracnose does not cause serious harm to sycamores, fungicide treatments are rarely warranted.
The leaves on my peach tree are puckered and reddish in color. What is the problem?
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