Yesterday I noticed my tree peony has started to bloom already — in fact, it went from just slightly open to fully in bloom in a few hours Saturday afternoon. My other peonies — all the herbaceous type — have a few tight balls on them, but no sign of bloom. I bought this one (sorry, I don’t have a record of its name) a few years ago at the very end of the peony season (fall), planted it in the cold and hoped for the best. It made it through its first winter and seems to like the moderately sunny spot where it is planted.
Unlike herbaceous peonies, a tree peony will develop a trunk-like stem and do not die to the ground each winter. They bloom on old wood and can get as tall as 5 feet. They also have a more striking foliage than herbaceous peonies. Each of the leaves is edged in purple. While my plant has been in the ground two (or maybe three) years, it is still dainty.
Most experts recommend some winter protection for tree peonies this far north (oops, I better do that this fall!) but otherwise they are not difficult to grow. (Update from 2018: I never covered my tree peony and it got better and better each year. Go figure.) They need four to six hours of sunlight and a moderate amount of fertilizer. It takes them five or more years to reach full size. That’s OK, though, because like other peonies they are long-lived. Most peonies will out-live the person who plants them by several decades.