I have two tree peonies in the front of my house. I often wonder why.
The blooms last about four days out of the year. They are ruined by both rain and sun. The plants take up a lot of space for such a limited show.
One of them is sending up an herbaceous sucker that I have to get rid of, undoubtedly because I was too lazy to saw out a tree root in order to plant it properly deeply. The peony story here from the Royal Horticultural Society's Plantsman magazine offers a superbly clear explanation of why tree peonies are grafted onto the roots of herbaceous peonies.
Tree peonies are expensive. White Flower Farm, whose photos of tree peonies have been making me swoon for the entire 20 years I've been gardening, charges $89.00 apiece for them. The ones I have are relatively cheap plants I paid about $20 apiece for. They were labeled 'magenta' rather than any variety name.
My tree peonies have frustrated me by being so much shorter than their reported height of 4 or 5 feet. However, the one pictured above, which has been in the ground four or five years now, suddenly seems to be getting taller.
Also, the four days when they do bloom, they are important. They start the second the tulips have finished. They bloom with my 'Purple Sensation' alliums and overlap the euphorbia polychroma. In another few minutes, we'll have roses and irises and herbaceous peonies and rhododendrons, and it will be another crazy parade in the yard. But not yet. Without the tree peonies, it would all be super-subtle here.
In addition, they make passersby gasp. Non-gardeners will often stop me to ask, "What the HELL is that?"
I'm from New Jersey. While I'm not sporting big hair or very high heels or lots of jewelry or tons of make-up like many Jersey women of my age, I do have showy impulses that manifest themselves in my gardening style. Plants that make my neighbors gasp are OK by me.