River birch tree leaves rolling and dropping. Anything I can do at this...
There are several possible causes for late spring/early summer leaf drop:Soil texture and drainage can also be factors. Trees planted in heavy clay soils tend to pond water in the previously-excavated planting hole, thus starving the tree roots of needed oxygen. The result of the oxygen starvation can be yellowing foliage or complete foliage drop.
Iron Deficiency - River birch are particularly susceptible to iron deficiency (chlorossis), which means the tree, for whatever reason, is not taking up that particular micronutrient. It doesn’t mean that the micronutrient isn’t available, it probably is, but if the soil Ph is too alkaline it can’t take it up. River birch prefer slightly acidic soils, and alkaline soils are common in parts of Ohio. Have your soil tested, and if appears this could be the problem apply chelated iron twice a year to amend the soil. Always apply product following label instructions exactly to insure the correct dosage.
Here’s a publication from the Univ. of Illinois Extension Service on iron chlorossis that might help determine if this is the problem http://hyg.ipm.illinois.edu/pastpest/200210a.html
Bronze Birch Borer - River birch are not as susceptible to bronze birch borer as some other varieties are, so this is not very likely the cause of your leaf drop. But here’s a Penn State Extension fact sheet about Bronze Birch Borer that could help you determine if it’s a possibility in your case: http://ento.psu.edu/extension/factsheets/bronze-birch-borerThank you for allowing us to help you with your gardening questions. Here are some other helpful websites: