The mimosa tree (Albizia julibrissin) is a very interesting and beautiful tree. It's fern-like foliage and fluffy flowers give it a very tropical look. However, it is considered INVASIVE in Pennsylvania by DCNR.
My neighbor has one planted right along our property line, and I can attest that it IS very invasive. I'm constantly battling seedlings, and the falling flowers stain the sidewalk. Some say that the flowers smell terrible as well.
The mimosa was introduced to the US and Europe from Asia in the 18th century and now grows wild in most Southern and Northeastern states. It can grow in a variety of soil conditions, preferring disturbed sites, and is very competitive, shading out other vegetation.
There are plenty of beautiful flowering native alternatives including dogwood, redbud, serviceberry, crabapple, and fringe trees.
Data Source: DCNR