Shrub · Rosaceae
Common Ninebark
Physocarpus opulifolius
A native shrub of peeling papery bark and richly colored leaves that changes as you look closer.
Full sun
Every 7–14 days
USDA 2–8
5–8 ft · 1.5–2.4 m
Overview
Ninebark shows its character in the bark first. On the older stems the outer layer lifts and curls away in thin, papery strips, exposing pale wood beneath and giving the arching branches a shredded, ridged texture that stands out most in winter once the leaves have gone. It is a rose-family native of eastern North America, cold-hardy to zone 2, drought-tolerant once rooted, and content in almost any soil.
The leaves carry the color. Lobed and toothed along their edges, they come in cultivars of deep purple, gold, copper, and wine-red, and in late spring the shrub sets flattened clusters of small five-petaled flowers in white to soft pink among them. On the dark and gold forms the leaf color holds from the moment the blades open until they fall.
The whole plant grows fast into a dense, rounded mass of upright and arching stems that wants space and full sun to color well. Crowded into damp shade, its foliage takes on the gray film of powdery mildew. Given room, it fills out as a solid, textured backbone shrub that reads well up close and from a distance.
Care
The short version: full sun draws out the deepest leaf color, average well-drained soil suits it since it adapts, and watering matters only through the first season. After that it is drought tough, wants little feeding, and takes a single prune a year right after the flower clusters fade.
Light
Ninebark colors best in full sun, where the purple and gold cultivars turn their richest and the pigment reaches every leaf. In partial shade the same foliage pales and flattens in tone, and the gray film of powdery mildew settles in more readily once the air goes still.
Water
A newly set plant needs regular water through its first growing season to push roots into the ground. Once rooted, ninebark is genuinely drought tolerant and asks for water only in a long dry spell. Let the top half of the soil dry between waterings, roughly every 7 to 14 days.
Soil
Ninebark takes to almost any ground. It grows best in average, well-drained soil but roots into clay, loam, sand, rocky, dry, and even wet spots. It runs across a wide pH from 5.5 to 8.0, so most soils suit it as they are.
Temperature
Ninebark is exceptionally hardy, standing winter cold to about -51°F (-46°C) and summer heat to 100°F (38°C). That reach covers hardiness zones 2 through 8, which is why the shrub turns up so often in cold-climate gardens.
Humidity
Outdoor humidity is nothing to measure here, and there is no target. Air moving through the branches matters more, since crowded, stagnant conditions leave the leaves damp and draw powdery mildew onto them.
Feeding
This tough native rarely needs feeding. If the growth looks thin and weak, a light application of balanced fertilizer in early spring is enough. Too much, nitrogen most of all, forces soft, sappy shoots that fireblight burns straight through.
Pruning
Cut ninebark right after the flowers fade and no later than mid-August, because next year's buds set on the old wood and a late cut takes them off. To renew an overgrown, leggy plant, cut the whole thing close to the ground in winter and let fresh stems rise.
Repotting
Ninebark belongs in open ground and rarely needs potting on. In a container, move it up when the pale roots circle the pot, push out the drainage holes, or water runs straight through.
Size & spacing
Ninebark builds into a substantial shrub, 5 to 8 feet (152 to 244 cm) tall and 4 to 6 feet (122 to 183 cm) across. Give it that full spread so air slips between the branches and the leaves dry, keeping mildew from taking hold.
When to plant
Ninebark is a hardy shrub with a wide planting window. New plants go in through the mild weather of spring or fall, and the small white-to-pink flower clusters open in late spring, roughly April through June, before the colored leaves carry the shrub through the rest of the year.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Spring or fall
- Harvest: Late spring (April to June)
Hardiness
USDA hardiness zones: 2–8
Temperature: down to -46°C
Troubleshooting
Ninebark gives little trouble, and what appears shows on the leaves and shoot tips far more than on the whole plant. Nearly all of it traces back to crowding and damp, still air. Match the look below to the cause and act before it spreads.
Blackened shoot tips bent over like a burnt hook
The scorched-looking tips are fireblight, a bacterial infection that turns the shoot ends a dead brown-black and curves them down into a tight shepherd's crook while they cling stiffly to the branch. The blighted wood looks charred against the healthy green around it. Cutting well below that darkened tissue, wiping the blades clean between cuts, and destroying the prunings clears it, and lighter nitrogen with dry-weather pruning keeps the black tips from forming again.
Fix:
- Prune out blighted wood well below visible damage
- Disinfect pruning tools between cuts
- Destroy removed material; do not compost
A chalky white bloom dusting the leaves and shoot tips
That pale, floury film is powdery mildew, a fungus that creeps across the leaf surface where shade and still air let it settle, and it stands out sharpest against the darkest foliage. It coats the upper leaves and the tender shoot tips in a gray-white haze you can rub away with a fingertip. Thinning the crowded stems, stripping the worst leaves, and moving the shrub into stronger sun lifts the film off; the leaves stay marked for a season but the plant holds.
Fix:
- Improve air circulation by thinning crowded stems
- Remove and dispose of badly infected foliage
- Site or move plants into full sun
Dark, angular spots peppering the leaf blades
These dark flecks and blotches are fungal leaf spots, small lesions that stipple the leaf blades and sometimes run together into larger patches. They mark the surface where the foliage sits wet and crowded, yet the tissue underneath stays sound. Raking off the fallen spotted leaves, opening the planting to moving air, and watering low at the base keeps fresh blades clean.
Fix:
- Rake up and dispose of fallen infected leaves
- Improve spacing and airflow
- Avoid wetting foliage when watering
Toxicity
There is nothing here to fear. Ninebark stays off the ASPCA poison lists and is treated as non-toxic to pets, livestock, and people alike. The most a large mouthful of the leaves might bring on is a brief, mild stomach upset, the same as overeating any leafy plant.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Ninebark is safe for cats and stays off the ASPCA poison list. A cat that bites into one of the toothed leaves may drool a little or have a brief stomach upset, no different from chewing any leafy plant.
Dogs None
Dogs are safe around ninebark. A big mouthful of the crinkled foliage may loosen the stomach for an afternoon, but there is no real poison in the leaves or stems to fear.
Horses Safe
Horses come to no harm from ninebark. It carries no toxin known to affect them, and the dry, woody stems hold little that would tempt a grazing horse.
Rabbits Safe
Rabbits, pet or wild, are safe with ninebark. They browse the soft young shoots at the branch tips, and the leaves suit their digestion.
Livestock Safe
Cattle, goats, and sheep graze safely around ninebark, since it holds nothing that would poison them. A goat may strip the tender new growth from the stems without any trouble.
Birds Safe
Birds are safe with ninebark. Many pick at the dry, papery seed capsules through winter and tuck their nests into the dense tangle of branches for shelter.
People Safe
Ninebark poses no poisoning risk to people. It is not grown to be eaten, so the leaves rarely find their way to a mouth, but a stray taste does no harm.
No special handling precautions are required; wear gloves when pruning if you have sensitive skin.
Varieties
Most ninebark sold today is a colored-leaf cultivar rather than the plain green species, and the difference is all in the foliage. These are the ones you are most likely to meet, grouped by the color and change of their leaves.
Diabolo
The famous dark cultivar, its leaves a deep purple so dark they read nearly black, softening toward green through a hot summer.
Dart's Gold
Its leaves glow a bright golden-yellow, the color burning clearest and holding longest where full sun strikes the foliage.
Summer Wine
A more compact form whose dark wine-red leaves throw the clustered white-to-pink flowers into sharp relief.
Coppertina
New leaves unfurl a bright coppery orange at the shoot tips, then deepen to red as they thicken and mature.
Amber Jubilee
Its foliage shows gold, orange, and amber all at once, the tones shifting across the leaves as the season advances.
How to propagate
Ninebark can be increased three ways, and the choice turns on whether a cultivar's exact leaf color has to carry through to the new plant.
Stem cuttingsEasy
Late spring to summer using softwood cuttings · 4 to 8 weeks to root
To hold a colored cultivar's exact leaf tone, cuttings are the surest route. Snip the soft, green, still-bending shoots or slightly firmer semi-hardwood pieces from late spring into summer, and pale roots break from the cut ends in 4 to 8 weeks. It is the most reliable of the three methods.
SeedModerate
Sow in fall or after cold stratification in spring · Several weeks to germinate; seedlings of cultivars vary
Seed raises the plain green wild form, sown in fall or given a cold spell before a spring sowing, with the little seedlings pushing up over several weeks. Seedlings from a colored cultivar scatter across a range of leaf tones and will not copy the parent's color.
LayeringEasy
Spring through summer · One growing season
Layering uses the shrub's own low, arching branches. Bend one down until it touches the soil and pin it there any time from spring through summer, and it grows roots along the buried wood over one growing season before it is cut free as a separate plant.
Myths
The name ninebark means the bark peels off in exactly nine separate layers.
The name catches the look of the bark, which lifts and curls away from the older stems in thin, papery strips, not a countable stack of layers. Nine is an old figurative number here, standing in for many rather than a precise nine.