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Maple Trees

The Maple Tree On My Front Lawn Is Looking Very Sick.
What Is Wrong?

By Jay Mclaren

It is not uncommon for many varieties of maples to develop a sickly unhealthy look during early August. There are a number of causes for this sickness and a couple of remedies.

In a very hot, dry summer maples and other trees experience water stress. This means that the tree is unable to take up enough water to compensate for the loss of moisture due to transpiration. This is a stressful situation for the tree and as a result it may loose some leaves. A disease called Anthracnose is then able to take hold, particularly in maples, resulting in a general sickly look and possible dieback.

However, this year without the hot dry weather, the problem is the very opposite - too much water. Diseases of all kinds thrive in damp weather. Unfortunately, we have had a surplus of coolish damp weather this summer. The disease, Anthracnose, thrives in very wet conditions.

The symptoms of this disease are usually found in the upper branches earlier in the summer. One or two branches may show signs of wilt, or defoliation, or of brown dry leaves. This decline in the health of the tree may be limited to only one branch the first year. However, this bacterial disease will spread to other parts of the tree, and it is not unusual for these trees to die over a period of two to three years.

Other diseases, such as, Leaf Spot may also cause injury to trees at this time of the year. A tree that has lost a lot of foliage, or a tree that has foliage that looks pale green, or that has turned brown, are all showing signs of these diseases. In an extremely dry summer, naturally the remedy is a lot of water. However, little can be done when the problem is too much water. Early fertilizing will help the tree outgrow these diseases. Fertilizing this late in the season is not wise. Feeding now will result in tender new growth, which is unable to survive our winters.

For trees that are in the early stages of these diseases, feed heavily with fertilizer spikes early next spring. In the meantime, dead branches of trees that are infected should be removed, as should any branches that now have only brown, dry, crisp leaves. By pruning out two to three feet below the injury you may retard the spread of the disease into other parts of the tree.

Unfortunately, these types of diseases are becoming more prevalent and seem to be of a particular problem in urban plantings where root growth is restricted. Exposure to salt as a result of street salting may also. Trees growing in the rural areas are less likely to have these problems. The application of a fungicidal spray for two or three sprays at 14-day intervals through the season may well help. Unfortunately, with large maples this is not a practical alternative.