Hello Gardeners, I’m Amanda McNulty with Clemson Extension and Making It Grow . Large seedlings that resulted from crosses between Bradford pear and other Callery pear cultivars are easy to spot --thickets of these white-flowered invasive species are in full bloom across the state. Bradford pear itself is self-sterile, it was selected from Asian seedlings grown in this country for its extreme success as a street tree that would flower its head off but produce no messy fruit to litter the street