Instructions for Growing Peonies

Timing

Plant out in autumn to allow the cool weeks required for healthy growth and flowering in spring.

Temperature

Peonies require around 6 weeks of temperatures below 40 degrees to grow successfully. They can handle frozen ground without issue and will not thrive if protected from winter conditions.

Planting

Peonies are surface dwellers. The bare root should be planted no more than an inch below the surface of the soil in a spot that receives at least 6 hours of full sun a day, preferably more. If the root is planted too deep or the plant gets too much shade, it will grow foliage, but it will not set flower buds. Dig your hole a little bit bigger than the root itself, put in a bit of compost or any other bone meals you like to use, and back fill until the crown of the peony root is just about an inch below soil level. Cover the whole root, press firmly around, water in, and do not cover in mulch.

Water & Fertilizer

Water is very important as roots are establishing and again after the first shoots appear in spring. Top dressing with compost at the end of the season is appropriate, as long as it doesn’t increase depth too dramatically.

Disbudding

If you would like your plants to bulk up quickly over the first couple of years, many people cut the buds off of the plant the first year it grows in order to encourage the plant to spend its energy on root growth. This advice is more for cut flower growers than the home gardener, in my opinion. A plant will know how to grow better than we can manipulate it and logic says that if it was “unhealthy” for the plant to grow a flower, it wouldn’t. So take that with any grains of salt that you’d like.

Pest Management

There is a myth about ants and peonies. Ants will crawl all over your peony buds enjoying the sticky sap they emit, but the peonies do not need them to do so in order to flower. They also do no harm. And more insects is always better for a healthy ecosystem, so I like to let them do their work. If I am harvesting a don’t want ants in someone’s centerpiece I either twirl them upside down for a minute to throw off the ant, or I dunk the head of the flower in a bucket of water for a second. Just let them dry off before you use them in your arrangements if you choose the second option so they don’t mold in the vase. Peonies aren’t super popular with deer because of their strong smell, but I’m never surprised when a deer eats anything.

Harvest

When the peony bud has reached what is colloquially known as the marshmallow stage (soft and as squishy as a marshmallow), you can give it a cut and put it in clean water. It will open pretty quickly after that and all you have to do is change the water every few days. If you prefer your flowers to grow on the shrub, it’s worth deadheading after the petals have dropped. Peonies are susceptible to black spot and powdery mildew, but it rarely affects future growth. At the end of every season, cut back your peony to a couple of inches above the soil level and compost all of the leaf material. Twice as many stems will grow out of that same root system every year!