My Japanese Maple weeping tree – the leaves are wilting, dry, brown. What should I do?
Although applications of strong chemicals can cause the leaf scorch you describe, the more likely reasons relate to the climate.
HEAT, SUNLIGHT AND DROUGHT
If the leaves of your Japanese Maple are browning on the tips or are scorched looking and curled, but the branches are still flexible and alive, that leaf scorch could be caused from too much sunlight and / or excessive heat.
Most, but not all Japanese Maples prefer some shade during the day. In their native habitat, Japanese Maples grow along partially shaded woodland borders or just under the canopies of larger trees.
We have experienced heat waves and, notably, extremely high UV indexes, this summer and many trees are suffering fron leaf scorch as a result.
Further, lack of water in the full sun or in windy sites can play a role.
Is the soil completely dried out? Make sure that you are keeping it moderately damp;especially for the first two years after planting. But be careful not to over-water the tree, since the damaged leaves are not working as well as they should be.
If the tree is otherwise healthy, next spring it will produce fresh new leaves. However, if the problem recurs next summer, you may want to consider moving the tree to a shadier, more protected part of the garden.
Too much moisture can have the same effect on the tree as too little. If the leaves have slowly turned brown or black, starting at the tips and moving to the base, this could be an indicator of root rot. You may have planted the tree in a poorly drained part of the yard.
To check for soil moisture, dig a small hole near the roots. If the hole fills with water, that indicates a severe drainage problem, especially if there’s been no rain for a few days.
If the soil is too wet and the stems and branches of the tree have begun to die, you may not be able to save it.
However, before giving up, check for any live wood. Starting near the top of the tree, use a knife to gently scrape away a very small section of bark on the stems. If the layer underneath is green, the stem or branch is still alive; if brown or tan, it is dead. Continue testing down the tree. If you are finding live wood, then the tree may be still be saved. (If more than 50% of the tree is dead, the odds for saving the tree are not good, but you can still try.)
Dig up and replant the tree in a drier location or create a new raised mound above the existing position and replant so that at least half the rootball is in the drier soil. That way the roots will grow down to the moisture instead of soaking in it. Although you are creating a mound, avoid making a ‘mulch volcano’. Make sure that there is no soil or mulch piled up over the tree’s root flare (where the trunk widens at the bottom).
Given the summer we are having, I suspect that the first issue — heat, strong sun and drought — is the culprit and that your tree will recover.
For additional information on planting and caring for Japanese Maples, take a look at Growing Japanese Maples: a Toronto Master Gardeners Guide. Click here to read it.