American barberry, Berberis canadensis Mill., is rare in much of it range where some states list is as endangered and/or extirpated, but introduced barberries such as common barberry, B. vulgaris L., and Japanese (purple-leafed) barberry, B. thunbergii DC., are invasive and even banned in some parts of New England. Being an alternate host for wheat rust is another reason barberry gets banned.
Barberries have spines on the main stems rather than leaves that are actually produced on lateral stems instead. Barberries are also reported to be eatable although they are described as very tart. The barberry shown here is a Colorado barberry, B. fendleri A. Gray, that I saw at Philmont Scout Ranch in July 2008.
A client has me to regularly do battle with overgrown purple-leafed barberries planted by the fly-by-night landscaper that broke his promise to be around to do maintenance. This would not be as much of a problem if (among other things) he had planted them at a spacing allowing for growth to a mature size.
