Ornamental · Paeoniaceae
Peony
Paeonia lactiflora
Plant it shallow in full sun, leave it be, and a peony will outlive the gardener who set it.
Full sun
Every 7–10 days
USDA 3–8
1–3 ft · 0.3–0.9 m
Overview
A peony is one of the longest-lived plants you can put in the ground, and a well-sited clump can outlast the person who planted it. It comes up each spring as a herbaceous perennial, throws out big, full flowers in late spring, then holds clean green foliage through summer before dying back for winter. The blooms run from soft pinks to clear whites, and many carry a real fragrance.
What a peony wants most is patience and the right depth. Set the eyes too deep and you'll wait years for a flower that never comes. Get the depth right, give it full sun and soil that drains, and it asks for almost nothing after that. The catch is that a peony resents being moved, so the spot you pick is the spot it lives.
These are cold-climate plants at heart. They need a real winter chill to set buds, which is why they thrive across USDA zones 3 to 8 and sulk where winters stay mild. The growth is slow and the rewards come late, but few perennials repay a gardener for as many decades.
Care
The short version: plant in full sun with the buds just 1 to 2 inches deep, in rich soil that drains well, water about once a week in the growing season, and keep the nitrogen low so you get flowers instead of leaves.
Light
Give a peony full sun, at least 6 hours of direct light a day, and it will flower well and shrug off most disease. It tolerates partial shade, but too little sun is one of the main reasons a healthy-looking plant never blooms.
Water
Water deeply about once a week through the growing season, then let the top of the soil dry before the next drink. The roots rot in soggy ground, so drainage matters as much as the water itself. Keep the spray off the leaves, since wet foliage invites blight.
Soil
Plant in rich, well-drained soil with plenty of organic matter worked in. A pH between 6.0 and 7.0 suits it, and the one thing a peony will not forgive is a wet, poorly drained site where the roots sit in water.
Humidity
Ordinary outdoor humidity is fine, so there's no number to chase. Good airflow matters far more, because still, damp air around crowded plants is what lets botrytis and powdery mildew take hold.
Feeding
Feed in spring with a low-nitrogen balanced fertilizer, and go light. Too much nitrogen pushes lush leaves at the expense of flowers, which is the opposite of what you want from a peony.
Pruning
Cut the stems right to the ground in fall and clear away every bit of debris, which is the single best move against botrytis blight. Deadhead spent flowers through the season to keep the plant tidy.
Size & spacing
A mature peony stands 1 to 3 feet (30 to 91 cm) tall and spreads about as wide. Give each plant 1 to 3 feet (30 to 91 cm) of room so air moves freely and disease stays down.
When to plant
Peonies run on a fall planting clock, not a spring one. Set or divide the roots in September or October so they settle in before the ground freezes, then watch for the big flush of bloom from late spring into early summer, with each plant flowering for about 2 weeks.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Sow: Not typically started indoors; propagated by division of dormant roots.
- Plant: Plant or divide roots in September to October so plants establish before winter.
- Harvest: Blooms late spring to early summer (May to early June); individual plants flower for about 2 weeks.
Hardiness
USDA hardiness zones: 3–8
Temperature: down to -40°C
Troubleshooting
Most peony trouble traces back to two things, planting depth and damp, crowded air. Read the early signs on the buds and lower leaves and you can usually fix the cause before it costs you a season of bloom. Match what you see below, then act.
Shoots blacken and buds rot under a gray fuzz
This is botrytis blight, a gray mold that strikes in cool, wet weather and rots young shoots and buds before they ever open. Cut out the withered buds and blighted stems the moment you see them, and clear every stalk to the ground in fall so the fungus has nowhere to overwinter. Space the plants for airflow and water at the base, never over the top.
Fix:
- Remove and destroy withered buds, spent flowers, and blighted shoots
- Cut stalks to the ground in fall and remove all debris
- Improve air circulation and avoid overhead watering
Healthy foliage but few or no flowers
The usual culprit is planting depth, since peony eyes set more than 2 inches deep rarely flower. Too much shade, a recent division, or a heavy hand with nitrogen will all hold blooms back too. Lift the crown in fall and reset it with the buds only 1 to 2 inches under the soil, give it at least 6 hours of sun, and be patient with young or freshly split plants for a few seasons.
Fix:
- Replant in fall with buds only 1 to 2 inches below the soil surface
- Move to a site with at least 6 hours of direct sun
- Allow recently divided plants a few years to mature
- Avoid high-nitrogen fertilizers
White powdery dust on the leaves late in the season
Powdery mildew shows up as a white film on the foliage once shade and still air let it settle in, mostly in late summer and fall. It rarely kills a peony, but it looks rough and weakens the plant over time. Pull and destroy the worst leaves in autumn, open the planting up for better air movement, and keep peonies in full sun.
Fix:
- Remove and destroy affected leaves in fall
- Improve spacing and air circulation
- Site plants in full sun
Toxicity
A peony is grown for its flowers, not for eating, and the plant carries a compound called paeonol that is most concentrated in the roots and bark. It is only mildly toxic, but a pet or grazing animal that chews the roots or stems can end up with vomiting, diarrhea, and a dull mood. Keep cats, dogs, horses, and small children from gnawing on it.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · Birds · People
Cats Mild
A cat that chews the roots or stems may drool, vomit, and turn off its food. The paeonol is concentrated below ground, so a real reaction usually takes a fair mouthful.
Dogs Mild
Expect vomiting, loose stools, and a dull, low mood after a dog digs into the roots or gnaws the stems. Small nibbles tend to pass without much fuss.
Horses Mild
Horses that get into the roots can come down with an upset stomach and diarrhea, often with a flat, listless air. It takes a good amount of the woody parts to set this off.
Rabbits Caution
The same paeonol that troubles other animals makes peony a poor choice for rabbits, so keep the roots and stems out of reach rather than risk a stomach they cannot empty.
Livestock Caution
Cattle, goats, and sheep are unlikely to seek peony out, but the roots carry enough paeonol to upset a grazing animal that does, so fence it off from pasture.
Birds Caution
Little is documented for birds, and the toxin gives no reason to assume it is safe, so keep curious pet birds away from the plant.
People Caution
No part of a peony is meant for the table, and the roots in particular can bring on nausea and stomach upset if eaten. Grow it for the flowers and keep small children from chewing on it.
Keep pets from chewing roots and stems; gastrointestinal upset is most likely with large ingestions.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
Peony cultivars number in the thousands, but a few old favorites turn up again and again. These are the ones worth knowing by name.
Sarah Bernhardt
A classic late-season double that opens fragrant, soft pink flowers when most peonies are already finishing.
Do Tell
A Japanese-form bloom that pairs pale pink guard petals with a deep rose-pink center.
Festiva Maxima
An old, very fragrant double white marked now and then with a fleck of crimson at the petal center.
How to propagate
Peonies are slow to share but easy enough once you know the rule, which is to divide the dormant root in fall and replant the eyes shallow.
DivisionModerate
September to October while dormant · Several years to reach full bloom after dividing
Divide a peony in September or October while it sits dormant. Lift the clump and cut it so each piece carries 3 to 5 buds, the eyes, along with a solid chunk of root, then replant with those eyes just 1 to 2 inches deep. The new divisions settle in over the next few years before they hit full bloom, so plant them and let them be.
Myths
Ants are needed for peony buds to open.
The ants come for the sweet nectar on the buds, not the other way round. The buds open fine without them, and the ants do no harm while they feed. Peonies bloom on their own, with or without the ants.