Question: When is the best time to plant peonies? Do you have any tips for growing them?
Answer: The best time to plant peonies is in the fall.
Peonies are one of the best-known and most dearly-loved perennials. This is hardly surprising, considering their sumptuous beauty and fragrance, trouble-free nature and longevity.
Peonies thrive almost anywhere in the country. If a peony is well situated and happy, it may bloom for 100 years or more with little or no attention.
Most peonies are hybrids. The basic types are herbaceous and tree peonies — both are descendants from Chinese species. Herbaceous kinds, largely descendants of the perennial Paeonia lactiflora, die to the ground in the late fall. Tree peonies, which are really a shrub, produce flowers on permanent woody branches and are chiefly descendants of P. suffruticosa.
Peonies will be healthier, more vigorous and more floriferous if they have ideal growing conditions. This means it’s worth spending some time upfront, choosing the right planting location and preparing the soil. Peonies prefer a sunny location with well-drained soil. Good air circulation around the plant is also important.
Do not plant peonies near large shrubs or trees. Work in plenty of well-rotted manure or compost, and incorporate high-phosphorus fertilizer.
Position herbaceous peony roots carefully, since planting too deep will prevent flowering. To prepare the planting hole for a bare root peony, dig the soil to a depth of 12-18 inches. Use a garden fork to loosen the sides of the planting hole as well.
Add a shovelful of compost and a handful of an all-purpose, organic, granular fertilizer to the bottom of the hole and then add a shovelful of the original soil. Build up a “cone” of this amended soil inside the planting hole and then position the peony root on top of the cone with its roots hanging down the sides.
It is very important that the “eyes,” or growth nodes, located near the base of the old stem end up no more than 2 inches below the soil surface. If the peony root is positioned deeper than this, the plant may grow well, but it will produce few, if any, blooms.
Container-grown plants can be planted similarly. Just dig a hole that’s twice as wide as the root ball, but no deeper. Amend the soil as above. When planting, make sure the soil surface in the pot is at grade when the new plant is in the ground.
Mulch the first year and renew the mulch each year thereafter. Be sure to keep the mulch away from the base of your peonies. If the base is covered with mulch, the plant reacts as if it has been planted too deep and will not produce as many, or any, flowers.
A yearly application of organic, all-purpose fertilizer and a top-dressing of compost is all a peony requires for good health.
Peonies rarely bloom the first year after planting. It often takes three years before you see an abundant display of flowers. Once the plants do start blooming, you can look forward to a lifetime of beautiful flowers. Colors include black, coral, cream, pink, purple, rose, scarlet, white and yellow.
Herbaceous peonies will reach a height of 2-4 feet. Peony plants rarely need dividing. If a clump becomes too large for a given space, or you wish to share some of the plant with a friend, fall is the ideal time for dividing.
Cut back the foliage and carefully lift the entire plant out of the ground. Use a sharp knife to cut apart some of the plant, making sure to create generous clumps of roots with at least three to five eyes per clump. Reposition the original plant back in the hole, taking care not to break off any of the relatively brittle roots or leave large pockets of air in the planting hole. Water until you are sure the moisture has reached the bottom of the hole and that the soil has settled around the roots.
Plants that have been divided in the fall may not bloom the following spring but will return to normal the next season.
Unlike herbaceous peonies, tree peonies are deciduous shrubs with woody stems that do not die back in the fall. They will grow 3-5 feet tall. Flowers may be single, semi-double or double and are commonly 6-8 inches wide. The most common flower colors include white, pink, and red; however, they are also available in yellow, purple and green.
Tree peonies grow rather slowly and often take four or more years to bloom well, but the results are worth the wait.
To gather peonies for bouquets, cut them just as the buds begin to open. Leave at least three leaves behind on every cut stem. Do not remove more than half the blooms on any clump. The object is to preserve leaf growth so that it nourishes the plant for the following year. Deadhead flowers to prevent seed formation.
Peonies benefit from a support system of wire stakes and rings to help them from flopping over when laden with flowers. Installing the support system when the shoots are small in the spring helps prevent mechanical damage to the new shoots.
The herbaceous garden peony and tree peony are popular, long-lived perennials that provide abundant flowers in the spring and summer. Peony flowers have a richness unlike any other. Home gardeners can create an exquisite and long-lasting display by understanding the types of peonies available and the proper planting requirements.