Last Updated on October 24, 2022 by Plant Mom Care
Peonies were cultivated in China much before 1000 BC, later being cultivated in Japan, Europe, and North America. These popular perennials consist of around 40 species and more than 6,500 hybrids, with some living for almost 100 years.
Tree peonies can be about 4 – 7 feet in height with a width of 4 – 5 feet while herbaceous varieties only grow about 1 – 3 feet tall and as wide. Depending on the type and variety, flowers can be small as 2 inches or large as 10 inches. They have tuberous roots that are an amalgamation of thin roots that absorb water and nutrients and thick storage roots.
Flowering varies among varieties, ranging from spring to summer, but all types must be planted in autumn, before the winter cold, as this enables the plants to establish roots before winter. Spring planting generally produces a poor flowering season. Flower colors vary from white, yellow, pink, red, coral, and maroon, with some changing color as the buds open.
Fragrance varies as well with some having strong rose-like aromas while others are lemon-like or have no smell at all.
Peonies Light Requirements
These plants can manage half a day’s worth of full sun but prefer growing under the full sun for 6 – 8 hours every day. Without sufficient light, they will produce fewer blooms and small flowers, and face potential fungal infection.
They need protection from gusts of strong winds, as their large flowers make them top-heavy. Use stakes to support them. Don’t plant them near other trees or shrubs, as they don’t like competing for light, food, and moisture.
They like to be watered moderately as overwatering often leads to problems like root rot and other issues. They need adequate drainage to prevent them from sitting in water-logged soil.
You only have to water them every week or so, depending if the summer months are hot or dry. Indications of under-watering are wilting, bud drop, and dry, discolored, foliage. Reduce or even stop watering them in winter when they’re dormant.
Once they are several years old, they become fairly drought tolerant, although they will have good watering in hot summers.
While they will tolerate a wide range of humidity, prolonged humid settings can encourage fungal infections.
Peonies prefer cooler climates in zones 3 – 8 and thrive better when they undergo cold winters. Most varieties need temperatures between 32 – 40°F for roughly 20 – 42 days as bud development is encouraged by cold temperatures.
However, protect potted peonies from prolonged freezing winter cold – frost won’t harm potted plants.
Herbaceous varieties prefer well-drained and slightly acidic soil. Tree peonies prefer slightly more alkaline soil.
If the soil is heavy and clayey, amend it with compost since they can grow in the same location for around 70 years, take the time to make up the right soil mix before planting.
The best time for repotting this plant is from October to March when it is dormant. First, water the plant as usual before repotting. It should be hydrated before digging it up. Remember, this plant doesn’t like being disturbed – hasty or rough handling can kill the plant.
Clip off all the foliage about 2 – 3 inches above the soil, and make sure you dig up the plant far from the roots. Let the roots dry to form a callus before repotting to prevent rotting. Repotting this plant requires a much larger container with satisfactory drainage since it will live in it for a long time.
Fill the pot with suitable soil amended with compost and make a shallow hole for roots – the eyes have to be close to the surface otherwise the plant will just produce foliage. Insert the roots and cover them with one or two inches of soil – the stumps of the stem should stick out from the soil.
Preferably, the eyes (small reddish buds) should be two inches below the surface in cold regions and one inch in warm climates. Press the soil down to remove air pockets, but do not compact it too tight. Water thoroughly.
These plants are normally propagated by separating the root clump, then planting the divided sections immediately. A peony might require division after around 10 years when it starts losing its vigor and gets root-bound. Autumn is best for this propagation – you can also divide the plant when you repot it. Just before dividing it, cut the foliage down to ground level.
Dig up the entire root ball, removing the soil by spraying it with water. Use a knife to separate and manipulate the tuberous roots into portions, each having 3 – 5 eyes.
Let the cut dry before replanting the separated divisions into large well-draining containers filled with suitable soil. Water them thoroughly.
Tree peonies require phosphate and iron and do well with an application of bone meal and sulfate in spring or use a 5-10-5 fertilizer. Spare the fertilizer for herbaceous peonies – mix in compost to the soil instead.
Stake the stems as they are not strong enough for their huge blossoms. Wire tomato cages can also work well, allowing the plant to grow in the center and providing support.
These plants do not require pruning or shaping to thrive. Pruning is only necessary for damaged or diseased foliage. Deadhead blossoms when they start to fade, cutting the stalk down to a leaf node leaf so the stem won’t stick out. Cut the foliage down to the ground level in autumn to prevent any diseases.
If you want larger flowers, snip off the side buds near the base of each main bud. To prolong the flowering season, leave them alone—they will flower later.
Remove suckers from the middle of tree peonies to thin growth and encourage good air circulation. Do not cut woody stems because tree peonies flower on old wood.
Peonies Common Problems
Peonies are particularly susceptible to botrytis (gray mold). To prevent this, do not plant them too close to each other to promote air circulation. Use copper soap fungicides to treat any infection.
You might notice many ants crawling on the flower buds. Don’t worry, they won’t harm the plant – they are enticed by the sugary droplets that form outside flower buds.
Why does my peony not flower?
This happens because the plant is very young or the eyes are planted deeper than 2 inches in the soil. If this is the case, the foliage will grow perfectly but very few flowers will appear.
Mature plants don’t like being transplanted. Divide the plant during transplantation to rejuvenate it, with each division having 3 to 5 eyes.
These plants love full sun and while they will still flower in partial shade, they’ll produce fewer flowers. Over-fertilization can also prevent the plants from flowering, particularly if nitrogen content is high.
Diseases like gray mold or botrytis blight can kill flower buds. These diseases generally affect these plants when the weather is cool and wet. Remove affected plant parts when you spot them and applying fresh mulch in winter prevents spores in the soil from traveling back to the foliage. Make sure the plants have good drainage and good air circulation.
How do you maintain peonies?
Water them moderately and use well-draining soil. Make sure the plants get sufficient light. Add compost or fertilizer as necessary. Support the plants with stakes or wire cages. To promote good bud growth, ensure the plants are exposed to low temperatures (32–40°F) and have excellent air circulation during the flowering season.
When should peonies be cut back?
Cut the stems down after the foliage has died in autumn to prevent disease.
How do you keep peonies blooming?
Make sure the plants get enough light. Each flower lasts about 7-10 days, with new buds developing below the main flower. The flowering season lasts in cooler weather and short in warm weather. Another tip to extend the flowering period is to plant other varieties that bloom at different times within the flowering period.
Do you cut down peonies for winter?
They have to be cut down in autumn to encourage new bud development in spring and to prevent disease. Pruning them down earlier can affect next year’s flowers.
Do peonies only flower once?
This depends on the variety as some varieties can flower twice a year while others seldom produce flowers again in the year.
How long can peonies live?
These plants can live a long time, some have been found to live for almost 100 years.