Even experienced gardeners encounter problems with their peonies from time to time. The good news is that most peony issues have identifiable causes and practical solutions. This troubleshooting guide covers the most common problems Australian peony growers face, helping you diagnose issues quickly and take corrective action.

Flowering Problems

My Peony Won't Bloom

This is the most common complaint from peony growers, and it has several possible causes:

Planted too deep: This is the number one reason peonies fail to bloom. The eyes (growth buds) should be no more than 5cm below the soil surface. If your peony produces healthy foliage but no flowers, this is the likely culprit.

Solution: In autumn, carefully lift the plant and replant at the correct depth, with eyes 3-5cm below the surface.

Insufficient cold: In warmer regions, peonies may not receive enough chilling hours. This is particularly common in coastal areas and northern parts of the peony-growing range.

Solution: Choose low-chill varieties. Consider whether your location is truly suitable for peonies, or whether you need to select more appropriate varieties.

Too young: Newly planted peonies often take 2-3 years to bloom. This is normal and no cause for concern.

Too much shade: Peonies need at least 6 hours of direct sunlight daily. Heavy shade will produce foliage but few or no flowers.

Recent transplanting: Peonies resent disturbance and may skip a season or two of flowering after being moved.

Buds Form But Don't Open

This frustrating problem, called bud blast, has several causes:

• Botrytis infection: Grey fuzzy mould on buds indicates fungal infection
• Late frost: Frost damage can kill developing buds
• Drought stress: Insufficient water during bud development
• Nutrient deficiency: Lack of potassium can cause bud failure

Disease Problems

Botrytis Blight (Grey Mould)

The most common and serious peony disease in Australia, botrytis causes soft, brown rotting of stems, leaves, and buds, often covered with grey fuzzy mould.

Prevention and treatment:

• Remove and destroy all affected plant material immediately
• Improve air circulation around plants
• Avoid overhead watering; water at soil level
• Clean up all fallen debris in autumn
• Apply preventive fungicide sprays in early spring if problems are recurring
• Space plants adequately for good air flow

Powdery Mildew

This fungal disease appears as a white, powdery coating on leaves, usually later in the season. While unsightly, it rarely causes serious harm to established plants.

Prevention and treatment:

• Improve air circulation
• Avoid overhead watering late in the day
• Remove badly affected leaves
• Apply sulfur-based fungicides if severe

Root Rot

Caused by waterlogged conditions, root rot shows as yellowing foliage, wilting despite moist soil, and eventually plant death.

Prevention:

• Ensure excellent drainage before planting
• Never plant in areas that stay wet
• Improve heavy clay soils with organic matter and gypsum
• Consider raised beds in problem areas

Pest Problems

Ants on Buds

This is perhaps the most common concern, but here's the good news: ants are completely harmless to peonies. They're attracted to the sweet nectar secreted by peony buds and do not damage the flowers.

Thrips

These tiny insects cause distorted, streaked, or bronzed petals. Damage is usually cosmetic and worse in hot, dry conditions.

Control:

• Regular watering reduces plant stress
• Remove heavily affected flowers
• Blue sticky traps help monitor populations
• Serious infestations may require insecticidal soap sprays

Aphids

These small, soft-bodied insects cluster on new growth and buds, sucking plant sap. They're usually more of a nuisance than a serious problem.

Control:

• Blast off with a strong water spray
• Encourage natural predators like ladybirds
• Apply insecticidal soap for heavy infestations

Nematodes

Root-knot nematodes can attack peonies, causing stunted growth and poor performance. They're more common in light, sandy soils.

Prevention:

• Buy certified disease-free stock
• Rotate plantings; don't plant new peonies where old ones grew
• Incorporate organic matter to support beneficial soil organisms

Environmental Problems

Flopping Stems

Heavy double blooms, especially after rain, can cause stems to bend or break. This is a common issue with many popular varieties.

Solutions:

• Install peony rings or grow-through supports before spring growth
• Use bamboo stakes and soft ties for individual stems
• Choose single or semi-double varieties if supports aren't practical
• Cut flowers just before they fully open

For detailed support options, see our guide on supporting peony blooms.

Leaf Scorch

Brown, crispy leaf edges, especially in summer, indicate heat or drought stress rather than disease.

Solutions:

• Ensure consistent watering during hot weather
• Apply organic mulch to keep roots cool
• Provide afternoon shade in very hot regions
• Accept that some browning in late summer is normal

Red Foliage

New peony growth is often red or purple, gradually turning green as it matures. This is completely normal, not a problem.

Yellow Leaves

Yellowing leaves can indicate several issues:

• Normal autumn senescence: Expected as plants prepare for dormancy
• Overwatering: Check drainage and reduce watering
• Nutrient deficiency: May indicate need for fertilising
• Root problems: Check for rot or pest damage

Preventing Problems

Most peony problems are easier to prevent than cure. Follow these practices for healthy plants:

• Plant at the correct depth (eyes 3-5cm below surface)
• Choose a sunny site with excellent drainage
• Space plants for good air circulation
• Water at soil level, not overhead
• Remove and destroy all dead foliage in autumn
• Apply appropriate fertiliser in late winter/early spring
• Monitor regularly and address problems early

With good cultural practices and prompt attention to any issues that arise, your peonies should reward you with healthy growth and beautiful blooms for many years to come.