Mallow Ninebark Plant Care

Mallow Ninebark (Physocarpus malvaceus) belongs to the Rosaceae family within the Physocarpus genus. Mallow Ninebark is native to western North America.

Mallow Ninebark displays a deciduous shrub, upright and spreading growth habit, reaching up to 6 ft tall with a spread of approximately 8 ft. Mallow Ninebark produces clusters of small white or pink flowers in late spring to early summer.

Leaf size: approximately 4 inches.

Water a young or newly planted Mallow Ninebark every 7–10 days, soaking the whole root zone, until it is established — usually one to two growing seasons. Established trees mainly need water during long dry spells. In a container, water whenever the top few centimetres of soil are dry.

Mallow Ninebark thrives in full sun to part shade.

Physocarpus malvaceus tolerates temperatures of 50–90°F. Mallow Ninebark prefers humidity levels of 30–60%.

Well-draining loamy soil with added compost for nutrients. Good drainage is essential for Mallow Ninebark to prevent waterlogging, which leads to root rot and fungal issues.

Feed Mallow Ninebark every 6 months during the growing season with a balanced, slow-release fertilizer at the rate on the label. Established trees in good soil often need little extra feeding, so let weak growth or pale foliage guide you.

Stop feeding by late summer so new growth can harden before winter.

The PlantoScan app can remind you when to water and when to fertilize each plant.

Choose a spot with full sun to part shade and well-draining loamy soil with added compost for nutrients. Avoid low spots where water collects after rain.

Mallow Ninebark is suited to USDA Zone 4a – 8b.

Plant container-grown or balled-and-burlapped trees in spring or early autumn, setting the root flare at soil level, and water well after planting.

Mallow Ninebark can spread to about 8 ft (2.4 m) and reach about 6 ft (2 m) tall. Space plants about 8 ft (2.4 m) apart so mature crowns don't crowd each other, and plant at least half that distance from buildings, fences and paths.

Planning a row or hedge? Try the tree spacing calculator.

Prune Mallow Ninebark while it is dormant in late winter: first remove dead, damaged and crossing branches, then thin lightly for shape.

If it flowers in spring, prune right after flowering instead so you don't remove next year's buds. Never take off more than about a quarter of the tree in one year.

Mallow Ninebark is hardy down to USDA zone 4a, so once established it can stay outdoors through winter in that zone and warmer ones.

Water deeply in late autumn before the ground freezes, and spread a 5–8 cm (2–3 in) layer of mulch over the root zone, keeping it away from the trunk.

Young and container-grown trees need extra protection: roots in a pot freeze much more easily than roots in the ground.

Mallow Ninebark can be propagated through softwood cuttings in early summer, division in spring. Similar propagation techniques also apply to ninebark plant care, which shares the same genus.

See all plants toxic to cats and plants toxic to dogs.

Mallow Ninebark is susceptible to aphids, spider mites, powdery mildew. Inspect the foliage regularly, especially along leaf undersides and stems. Treat infestations promptly with insecticidal soap or neem oil to prevent spread.

Yellow leaves, brown tips or drooping? See common plant problems and how to fix them.

Mallow Ninebark grows outdoors in USDA Zone 4a – 8b. It survives winters down to planting zone 4a. Mallow Ninebark is native to western North America.