Can anyone tell what variety of plum tree we have? It was already at our house when we purchased it last fall, so we don't know how old it is or anything. This summer it produced a decent crop of plums. The leaves start out purple in the spring, turn dark greenish/purple in the summer, and then back to purple in the fall. It has pink blooms in the spring. The fruit are about 1-1.5 inches wide when ripe, dark purple in color and the flesh is red/purple. They are also sweet tasting. We live in Colorado in zone 5b. Any ideas?