What would spring be without a few peonies in the garden? There are few other plants that are as completely bomb-proof, explode out of the cold, spring ground with more force, and erupt into color with as much chutzpah. Let’s face it, peonies have earned their place in the grand pecking order of the garden. And pass along peonies from grandma’s garden … that’s just priceless stuff.
But as wonderful as peonies can be at their best, many older varieties lack a bit in the area of garden follow-through. While there are many modern varieties that are boisterous flower machines with thick, sturdy (read non-flopping) stems and quality foliage, many older varieties tend more toward the one-hit wonder end of the spectrum. First, they bloom. Second, they flop. Third, a moment of inattention leads you to inadvertently run over the flopped blooms with the lawn mower, spreading a dusting of former peony petals evenly across the crisp, green lawn.
Finally, you try to distract your spouse by whisking him/her off to a “spontaneous” long and drawn-out, fancy dinner in the hopes that it will be dark by the time you get home and by morning the petals will have dried up and blown onto the neighbor’s lawn.
You’re smiling ... you’ve been there.
Lesser known in garden circles are the so-called tree peonies that, contrary to what the name would indicate, are not trees but rather, shrubs. Tree peonies are native to some particularly stressful parts of Asia including the steppes of Mongolia, parts of China and Tibet. In their native range, they can see summer temperatures over 100 degrees and winters at better than 20 below zero. But regardless of those extremes, they produce stunningly beautiful, 6-inch diameter flowers on 4 to 5-foot tall shrubs.
OK, enough with the peony bashing. Let’s get to the good stuff.
Back in the 1940s, an enterprising Tokyo gardener by the name of Toichi Itoh decided to cross the traditional herbaceous and woody peony species. People had tried it forever (after all, both types of peonies had been cultivated in China for a dozen or more centuries) and surely someone else had thought of it. Well, Itoh had a unique idea. Rather than dust tree peony pollen on a herbaceous peony like everyone else (in the wild, tree peonies tend to bloom before the herbaceous species) he forced a herbaceous peony to bloom early and used its pollen to fertilize a tree peony. Voila … the birth of the Itoh (now called, intersectional) peony!
Intersectional peonies are quite simply the rock stars of the peony world. They retain all the iron-clad adaptability of their parents. Just give them most of a day of sun and about any soil you can cleve with a spade and they’re happy as a clam at high tide. Their stems are stocky and sturdy, alleviating the spring flower flop and protecting you during any occasional lawn-mowing attention lapses. Large, billowy spring flowers come in a range of flowers from white to yellow, pink, fuchsia, red and even some coppery shades. The flower display lasts longer than either of the peony parents.
But one of the best advances brought with the new intersectionals is the fresh green foliage that looks good through most of the summer. Most named varieties remain free of the mildew that ravages so many traditional herbaceous peonies.
So if these intersectional peonies are so fabulous, why haven’t you heard of them?
The answer is cost.
For decades, intersectional peonies were relegated to the ranks of the peony collector. Who, after all, would plunk down $150 or more for a small, container-grown plant that may take another couple of years to produce its first flower? Because of its slow propagation in nurseries, cost made wider distribution pretty unlikely among most of us gardeners who tend to be … a tad frugal.
Fortunately, for a number of years, the Yew Dell Botanical Gardens staff has been working with a couple of North American producers who figured out how to propagate intersectional peonies in tissue culture. TC, as it’s known in the trade, allows a grower to place a small piece of surface sterilized plant tissue (part of a stem, leaf or root) in a little baby-food-sized jar, and coax it to make a gazillion little shoots that can then be rooted and grown on to mature size. The TC process has significantly dropped the price of finished intersectional peonies, which can now be sold in the retail market for half or less of their former price point.
And prices continue to come down. Today, with the costs significantly reduced, we’re able to get dozen of varieties of these amazing plants into the market.
This article was originally published in the Courier Journal on May 19, 2023.