Ninebark

Sun

Full sun to partial shade. Flowering and coloured foliage are usually best in full sun; light afternoon shade can help in hot climates.

Water

Water regularly while establishing. Established plants tolerate some drought, but benefit from deep watering during prolonged dry spells.

Soil

Adaptable to clay, loam or sandy soil, including alkaline ground. Prefers reasonably moist, well-drained soil but tolerates occasional wet conditions.

Height

5-10 ft (1.5-3 m); compact cultivars are smaller

Spread

5-10 ft (1.5-3 m); compact cultivars are narrower

Flowers

Late spring to early summer; rounded clusters of white to pale pink flowers, followed by inflated seed capsules that often turn reddish.

Foliage

Alternate, three- to five-lobed leaves, green in the species and purple, copper or gold in selected cultivars. Autumn colour varies from yellow to reddish brown.

Growth

Moderate to fast

Care needed

Low

• Water deeply during the first growing season whenever the root zone begins to dry.
• Apply 2-3 in (5-8 cm) of organic mulch, keeping it clear of the stems.
• Feed only if growth is weak; a light spring dressing of compost is usually enough.
• Allow space for the mature spread so air can circulate through the branches.
• Remove unwanted suckers at ground level if the clump begins to spread beyond its allotted space.

Pruning. Prune just after flowering, removing up to one-third of the oldest stems at ground level and shortening awkward branches selectively. Hard renovation pruning in late winter is possible, but sacrifices that year's flowers.

Late winter

Remove dead or damaged wood; renovate a severely overgrown shrub only if you can forgo the coming flowers.

Spring

Plant when the soil is workable, water thoroughly and mulch around the root zone.

Late spring

Check young growth for aphids and watch for powdery mildew as the canopy fills out.

Early summer

After flowering, thin out a few old stems if needed rather than shearing the whole shrub.

Summer

Water newly planted shrubs during dry weather and check that mulch is not touching the stems.

Autumn

Plant in mild areas while the soil is still warm, and remove unwanted suckers.

• Plant as an informal hedge or boundary screen, leaving room for its arching branches.
• Use green-leaved plants in native shrub borders with coneflowers, asters and grasses for a layered wildlife planting.
• Set purple-leaved cultivars behind pale flowers or fine-textured grasses for foliage contrast.
• Place near a winter path where the peeling bark can be seen after the leaves fall.

Garden styles it suits: English country, Wildlife garden, Low-maintenance, Native hedgerow, New perennial (prairie) and Winter interest.

Plant it with: Purple coneflower, Black-eyed Susan, Switchgrass, Hardy geranium, New England aster and Wild bergamot.

Wildlife: Flowers provide pollen and nectar for bees and other insects. Dense branches offer shelter for birds, and the foliage supports some native moth larvae within its North American range.

• Powdery mildew: white patches or distorted young leaves are common on susceptible cultivars. Improve spacing, avoid excessive nitrogen and choose a mildew-resistant cultivar when replacing a badly affected plant.
• Aphids: colonies can curl tender shoots. Wash them off with water and allow ladybirds and other predators to help control them.
• Stem cankers and dieback: remove affected stems back to healthy wood in dry weather, disinfect tools between cuts and reduce drought stress.
• Few flowers: shade or pruning before flowering may be responsible. Give the shrub more light where practical and do routine pruning immediately after flowering.

Ninebark is not known to be toxic to people, cats, dogs or horses, although species-specific safety information is limited. No part is intended as food; seek medical or veterinary advice if ingestion causes symptoms.

• Guelder rose (Viburnum opulus)

  Its maple-like leaves grow in opposite pairs, unlike ninebark's alternate leaves. It produces fleshy red fruits rather than dry, inflated capsules.

• Vanhoutte spirea (Spiraea × vanhouttei)

  It also has arching branches and white flower clusters, but its leaves are smaller and more finely toothed, and its fruit lacks ninebark's conspicuously inflated capsules.

Physocarpus comes from Greek words for bladder and fruit, opulifolius refers to leaves resembling those of guelder rose, and ninebark describes the many peeling layers of older bark.

Propagation. Take softwood cuttings in late spring or semi-ripe cuttings in summer, or separate rooted suckers while dormant. Seed-grown plants vary and will not reliably reproduce a named cultivar.

Accepted botanical name

Physocarpus opulifolius

In the US and Canada

Native in Canada and the lower 48 states.

Native range

Alabama, Arizona, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kansas and Kentucky.

Measured

Soil pH 4.5 to 6.5. Average height 300 cm.

Sources: GBIF (CC BY 4.0), USDA PLANTS and Trefle (CC BY 4.0). The care and design notes are LandscapeGPT's own.