You've got to draw a line somewhere, and Canada plum decided to draw it here. It is fairly common around here, immediately north of the Ohio border. It is considered extirpated in Ohio. That's not unlikely. This small tree is easy to spot, so if it was still a Buckeye, they would probably know. The flowers are white when they first open, turning pink as they age. Like other plums, they are worth a stop and sniff. Wonderful fragrance. Canada plum has been known from CT, IA(E), IL, IN, MA, ME, MI, MN, NH, NY, OH(X), VT, WI, MB, NB, NS, ON, and QC. Lenawee Co MI, 5/9/11.