SEATTLE — Peonies are one of the most enduring garden perennials. They produce lush flower displays every spring. These cherished perennials come in a rainbow of colors. You can grow white, yellow, pink, red peonies and several other hues.
All peonies prefer full-sun and well drained soil. They are subject to fungus disease if they are crowded or are planted in a location with poorly drained soil.
There are 3 main kinds of peonies, although there are plenty of varieties of each type. Herbaceous peonies typically grow from 2 to 4 feet tall. They form a shrubby mound in the landscape with dark green leaves and pretty flowers. The blooms appear during the window where spring transitions to summer. Herbaceous peonies usually strut their stuff as spring bulb flowers are fading and before summer perennials kick into gear. The flowers generally last for a week to 10 days. That may seem short, but by including a mix of early- mid- and late-flowering varieties, you can extend the blossom fest to nearly six weeks.
Individual herbaceous peonies live for 50 to 100 years. They’re a perennial that can grace a garden with color for generations.
Herbaceous peonies never need dividing. As long as they are in the right conditions these long-lived plants flourish and bloom for years with little care. There is a misconception, however, that they can't be divided. Nothing could be further from the truth. Peonies are easy to divide once they die back in fall, and it's a great way to make new plants. Just make sure that each division has 3 to 5 growth eyes (buds) along with 3 or more thick, healthy roots. When replanting, choose a sunny location with well-drained soil, and work plenty of compost into and around the planting hole. When you plant the divisions, make sure the buds are facing up and protrude just above the soil surface. Don't get bummed if your new plants don't bloom for a couple of years.
Peonies live for over 100 years, so they aren't in any hurry to flower and raise a family. Once they begin blooming again, they'll continue to put on a star performance every spring well into the future.
Another kind of peonies are tree peonies. Tree peonies are the national flower of China. The magnificent flowers can be as big as dinner plates, and their unusual form adds beauty and structure in the mixed border. Best of all, tree peonies can be amazingly long lived. There are reports of tree peonies living for more than two centuries in China. Of course if you want your tree peony to live to a ripe old age, it's important to plant and care for it properly. For starters, plant your tree peonies differently than your herbaceous peonies. Unlike herbaceous peonies that won't tend to bloom unless they are planted no deeper than they came out of the pot. Tree peonies, on the other hand, should be planted considerably deeper because they are grafted on herbaceous peony roots. The herbaceous roots are there only to give the tree peony stems time to root before the herbaceous roots die out.
Therefore tree peonies should be planted so the graft is 4 to 6 inches below the soil surface; otherwise, the herbaceous root stock will survive and an endless stream of herbaceous peony suckers will grow into your tree peony. Tree peonies resent competition, and should be planted in an open, uncrowded location in full-sun and well-drained soil. Mix in a half handful of bone meal as well as a cup of organic flower food into the planting hole. Right after planting, and every April afterwards, work in a cup of alfalfa meal around the drip line to increase blooming. Choose carefully when deciding where to plant your tree peony. Once established, they resent transplanting. Then be patient because it can easily take 3 to 5 years before it will finally begin to flower. Considering that you'll get to enjoy blossoms every year for the next 200 years, that doesn't seem too long to wait. If your tree peony is getting too tall, has become thin and leggy, or just won't branch out, don't be afraid to prune it. Take your time with the project. Only cut one or two branches per year at the most. You can do the pruning before growth occurs in spring, but it works equally well if you do it soon after the blossoming period is over. Of course, there's no guarantee that it will work on your peony. If my advice does your expensive plant in, just remember that we learn from our mistakes and that the greatest plant experts are the ones who have murdered the most plants.
The other kind of peonies are known as Itoh peonies (or intersectional hybrids). They've been around since the 1940s but until recently, these crosses were extremely difficult to find and you could expect to pay over $1,000 for one. Now, they are finally becoming available and affordable for home gardeners. Itoh peonies are crosses between tree and herbaceous peonies and feature the best traits of both parents. The bushy plants grow like an herbaceous peony, but they are crowned with the huge dinner plate sized flowers of tree peonies. The blooms come in a wide range of colors and occur on such strong stems that they don't require staking. An exciting trait is that a mature Itoh peony can be expected to bear 30 to 50 flowers that open over several weeks in late spring. The blossoms even emit a pleasing spicy sent. Plant them in a sunny location in well-drained soil amended with compost. Water well the first season to establish a strong healthy root system. Cut the stems down to the ground in autumn as you would herbaceous peonies. The one difference is that since the flowers open over an extended period, Itoh peonies look best if you deadhead them. Use care to avoid injuring emerging flower buds when you remove the spent flowers to ensure a long blooming period.
Peony blooms make wonderful cut flowers, but spray them off with the hose before bringing them in the house, especially if you plan to use them in centerpiece bouquets at a dinner party. Ants that are attracted to a sweet substance on the buds often hide in the flowers and nothing will embarrass the living tweetle out of you more than if your dinner guests discover uninvited guests hiding among their serving of brussels sprouts casserole!