We all know about peonies. We’ve all seen peonies; we all remember our grandmother’s peonies.
We take peonies for granted, but did you know that peonies have been grown and cultivated for centuries? Initially used in China for flavoring food and medicinal purposes, their obvious floral attributes encouraged cultivation to enhance their appearances as well as their usefulness.
Gradually spreading across China, Korea and Japan, they were introduced into Europe in the 1600s where they were appreciated for both their medicinal qualities and appearance.
Today we recognize 35 different peony species native to Asia, Europe and Western North America and up to 6,500 cultivars around the world.
Peonies come in three common types: tree (Paeonia suffruticosa), herbaceous (whose species can vary) and Itoh (intersectional), a hybrid of tree and herbaceous. They are further classified by their flower form, differentiated by the number of flower petals and their arrangement.
Herbaceous and Itoh peonies grow to a height of 1-3 feet with an equal spread. Tree peonies reach heights of 7 feet spreading to 4-5 feet. Their flowers can be 7-10 inches across.
Peonies need very similar growing conditions and care with a few minor differences. They like full sun in most zones.
If you live in Arizona, this might need to be adjusted, but here in the Pacific Northwest, plant them in full sun in well-drained soil. Peony roots will rot if they stand in water, so choose your spot carefully or prepare a raised bed.
Once planted, peonies need very little maintenance and can flourish for years. Plus, you’re going to like this: Deer don’t like peonies; yep, deer proof!
Peonies do not like to be moved and respond poorly to transplanting, so, choose your site carefully when planting to avoid moving them.
If you buy tubers, plant them in the fall (September-October). It’s best if they’re settled before the ground freezes. Dig a generous hole (18x18 inches), incorporate some organic material with the natural soil, build a mound within the hole and set the tubers, eyes facing upward, on top of the mound and then backfill.
Do not plant too deeply; 2-3 inches below the soil surface for herbaceous and Itoh peonies, 4-6 inches for tree peonies. Take into account soil settling; proper soil depth for peonies is important. If you’re planting a potted peony, follow the same directions and plant it no deeper than it grew in the pot.
You probably don’t need to fertilize your peony, but if you can’t help yourself, use a tulip fertilizer and sprinkle it sparingly around the dripline, not the crown.
Alternatively, apply compost or well decomposed manure in early summer after blooming. Regardless, they don’t need feeding every year.
Keep weeds away from the crown area. Herbaceous and Itoh dislike root competition. Tree peonies are easier going but still shouldn’t be planted near other plants; they’re going to get big.
Peonies need to be watered regularly the first year after planting, but after they are established, give them a good soaking during dry periods. Don’t overdo it — no soggy roots. They flourish with very little attention.
Give the plant time to grow before expecting big blooms. Like roses and lilies, peonies need a couple of years to establish themselves before satisfying your big flower addiction.
Peony blooms are very large and will plop over unless supported. Use a three-legged grid support or tomato cage to support the plant. Deadhead regularly during bloom time, cutting back to a strong leaf.
When bloom time is over, let them be. Some gradually die back and others remain growing. Just leave them alone.
Come fall in the valley, you won’t need to mulch, just cut the foliage to the ground, clear it out to prevent overwintering diseases and leave them alone. Peonies need a little chilling to encourage bud formation, so it’s OK if they get cold.
Peony varieties bloom from mid-May to late June. Choose varieties that bloom early, mid-season and late to have a continuous peony party in your garden.
They are very versatile in garden design. Choose any variety for a stand-alone specimen, plant a hedge of them, or incorporate them other perennials and annuals.
In mixed beds, keep other plants at least 12 inches or more from the peony crown. Remember they don’t like their crowns crowded. Some peonies are fragrant and some are not. If fragrance is important to you, do your research and find one that rocks.
Peonies as a rule are disease-free. Here in the Pacific Northwest we do have one fungus that can do some real damage to peonies: botrytis. Botrytis also affects roses and other plants causing brown leaf stippling, stem dying and shriveling and rotting blooms.
If your peony has botrytis, cut out and dispose of the infected parts (in the garbage, not the compost bin) to minimize the damage. The good news is that WSU researchers are working on identifying the different kinds of botrytis. Proper identification will lead to better management options for all plants.