Black locust, Robinia pseudoacacia, is a colonial tree
that can quickly regenerate after a forest disturbance such as a fire or timber
harvest. Due to various pests such as
borers and now Japanese beetles these spine covered stems are relatively short
lived, but can reach a size suitable for fence post and the tendency to form
suckers and produce dense thickets makes them more available than other
suitable untreated wood post. They were
often planted, including by my grandfather, for the purpose of growing fence
post due to the wood being very durable, but now it is considered invasive in both
Besides the black locust tree there are a couple of shrubbier locust species and these are bristly locust, R. hispida, and clammy locust, R. viscosa. One of the most noticeable differences is that they both have pink flowers rather than white flowers while the difference between bristly locust and clammy locust is the bristles. There are several other taxa that are either consider to be varieties of bristly locust, clammy locust, or hybrids between each combination of the three locust native to Alabama as well as one with New Mexico locust, R. neomexicana, since only black locust overlaps that range. One of the variations between the varieties seems to be the amount of fruit although it may be confusion with hybrids which may lack fruit. I have seen pink flowered locust with and without bristles and they are often on roadsides in relatively remote areas. Additionally they are useful for land reclamation since they sprout even more if erosion exposes the roots. I’ve been hoping to get permission to get divisions from a few local populations.