cottonwood tree rust

treeluver

i was just thinking about this today and remember that every fall our eastern cottonwood tree will get what looks like little dots of a powdery rust color substance on them, it covers the leaf and the leaf turns brow and falls off prematurely, it happens every fall, i don't think it is normal, how do i treat it, and if left untreated will it kill the tree over time?

treeshaveneeds

If it really is rust, clean up ALL the leaves in the fall and put them is a hot compost heap, or get rid of them. This would include other cottonwoods with infections in a 1 mile radius.
Do it every year, cross your fingers, say a prayer in church every sunday and meditate regularly with your tree, and you might solve the problem. Fertilizing with good organic fertilizers or good compost can also help.

Usually it is not a big deal for the tree. If the infection on a leaf is really bad, the tree just drops the leaf, and if there is enough time in the season, grows a new leaf.

TreeSpecialist

Cottonwood trees do this every year - as early as July 1 in this part of the country.

Two leaf rusts commonly attack cottonwoods in the United States. Rust of eastern cottonwood is caused by Melampsora medusae; M. occidentalis infects black cottonwood. Other poplars, including hybrids, are also susceptible to these two fungi.

"Treating" it would be a waste of time. The biggest problem with cottonwood trees is that they seldom get enough water unless they are growing in their natural habitat next to a stream or creek.

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treeluver

that would explain why it dosen't grow as fast as the ones by the river, its planted in a lower lying part of the yard where the rain collects, but this dries up fast too