Problem with River Birch leaves
Our client brought in some clippings from his river birch tree. He has a clump of 3 trees and 2 of them are affected. The leaves are curled and dying around the edges. He bought the trees 3 years ago from Home Depot and the leaf curl started 2 years ago. The trees are in his yard in the city, in full sun. They are about 12 feet tall and have continued to grow with this going on. I found a MSUE article about this happening in Northern Michigan from 2007 but it does not state what it is and how to treat it. Any help is appreciated. Thanks.
I think the MSU article in 2007 to which you refer is on a condition called “mouse ear disorder”. This could be the problem. Mouse ear is a fairly newly discovered problem, and in nurseries is treated with application of nickel sulfate. This may not be available to homeowners, so I would not go out and try this without an exact diagnosis and recommendation from a diagnostic lab.
Other possibilities are too little water( birch need to be moist down to about 10-12 inches in the soil and lawn sprinklers do not reach that far), or frost damaged buds. However, newer leaves at the tips of branches and opened well after late spring frosts should be normal.
Another possibility is Herbicides, especially weed killers put down on lawns, can cause distorted leaves on trees, including birch. If this issue doesn’t show up until later in the season, say after lawn weed and feed was applied, that would be an indication of herbicide injury.
As you can see, accurately reporting when the distorted leaves first begin to show is important.
Since this is an ongoing problem, I suggest the client send fresh twig samples having distorted leaves, and any normal leaves available, to MSU Plant Diagnostic lab. Send pictures of the whole tree with a description of how the tree is watered, and what kind of weed and feed chemicals - and when- are put on surrounding lawn. Describe what time of year the distorted leaves begin to show. And ask them “ could this be nickel deficiency/mouse ear disorder on birch?” The website is https://pestid.msu.edu. There may be a fee for diagnosis.
Here is a reference for your client
Mouse ear or herbicide injury?
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