Black Locust (Robinia pseudoacacia) on Aug 17, 2009
Submitter has sample
Description of specimen
It's a black locust tree, I didn't see it on your list, but when I looked it up online, it said that it is native to the Ozarks and the southern Appalachians and that it has been found in Europe, Missouri and Indiana and the northeastern US. It is a horrible menace, it has killed off everything else in my yard and is even growing out of the floor in my basement! I don't know if you can help me, but I don't know what else to do.
Yes, black locust is a problem species that the city manages on some of its properties, but it is not yet widely considered to be invasive. On our own sites, we have seen that cutting down a black locust often causes the roots to grow vigorously as new trees, so treatment would have to be aggressive, either through frequent cutting of resprouts, or use of systemic herbicide. Unfortunately, there are no programs in place to help landowners with either strategy. I wish there were more we could do. Feel free to get back in touch if you have further questions, and thank you for your email.
-Mitch Bixby
mitch.bixby@bes.ci.portland.or.us
Mitch Bixby
Sept. 22, 2009, 3:53 a.m.