Winterberry

Sun

Full sun to partial shade; full sun usually produces the heaviest berry crop.

Water

Keep the soil consistently moist, especially during establishment and fruit development. Tolerates wet ground and occasional flooding but performs poorly in prolonged drought.

Soil

Moist to wet, acidic soil rich in organic matter; tolerates clay. Aim for pH 4.5-6.5 and avoid chalky or alkaline ground.

Height

6-12 ft (1.8-3.7 m); compact cultivars stay smaller

Spread

6-12 ft (1.8-3.7 m), eventually wider where suckers are allowed to spread

Flowers

Small, inconspicuous greenish-white flowers in late spring to early summer; male and female flowers grow on separate plants.

Foliage

Oval, toothed, dark green leaves; autumn colour is usually yellow-green and often modest.

Growth

Slow to moderate

Care needed

Low

• Plant a compatible male within about 50 ft (15 m) of female plants, checking that their flowering times overlap.
• Water deeply during dry spells; do not let newly planted shrubs dry out.
• Apply 2-3 in (5-8 cm) of organic mulch, keeping it clear of the stems.
• Feed lightly in spring only if growth is weak; test the soil before treating yellow leaves.
• Remove unwanted suckers at ground level if you need to contain the clump.

Pruning. Prune lightly in late winter, after enjoying the berries, removing dead wood and a few of the oldest stems at ground level if crowded. Avoid routine shearing or heavy annual pruning, which can reduce flowering and fruiting.

Autumn

Plant while the soil is workable, water thoroughly and mulch; choose a suitable male pollinator if buying a female.

Winter

Leave berry-laden branches for display and birds; cut only a few if gathering stems for indoor arrangements.

Late winter

Remove dead or damaged branches and thin crowded older stems sparingly.

Spring

Refresh mulch and check soil pH if leaves emerge yellow between green veins.

Late spring to early summer

Check that male and female plants flower together and avoid spraying insecticides on open flowers.

Summer

Water during dry weather and remove unwanted suckers.

• Mass female plants beside a pond or rain garden, with a compatible male nearby, for winter colour.
• Place against dark evergreens so the bare, berry-covered branches stand out.
• Combine with red-stemmed dogwoods and sedges for a winter border on moist ground.
• Use in an informal woodland edge or wildlife hedge with other moisture-loving shrubs.

Garden styles it suits: Woodland, Wildlife garden, Bog garden, Winter interest, Native hedgerow and New England.

Plant it with: Red-osier dogwood, Summersweet, Cinnamon fern, Red chokeberry, Highbush blueberry and Tussock sedge.

Wildlife: Flowers attract bees and other pollinating insects. Birds eat the berries, often later in winter, although the crop may disappear earlier; dense clumps also provide shelter.

• Few or no berries: check that the plant is female and has a male winterberry flowering at the same time nearby; improve sunlight and avoid heavy pruning.
• Yellow leaves with green veins: alkaline soil can cause iron chlorosis; test the soil and address the pH, or move the shrub to suitable acidic ground.
• Leaf spots or powdery mildew: improve airflow, water at soil level and clear fallen diseased leaves; minor infections rarely need treatment.
• Wilting or dropped fruit during drought: water deeply and renew mulch to keep the root zone moist.

Toxic if eaten by people, cats, dogs or horses. Berries and leaves contain saponins and can cause vomiting, diarrhoea and abdominal discomfort; small accidental ingestions usually cause mild gastrointestinal illness, but larger amounts can be more serious. Keep berries away from children and pets, and seek medical or veterinary advice after ingestion.

• Possumhaw (Ilex decidua)

  Also a deciduous holly with red berries, but its leaves are generally narrower and spoon-shaped, with rounded teeth rather than winterberry's sharper serrations.

• English holly (Ilex aquifolium)

  Keeps glossy, leathery leaves through winter; many leaves have strong spines. Winterberry loses its thinner, finely toothed leaves.

• Red chokeberry (Aronia arbutifolia)

  Bears red fruits in terminal clusters and usually develops strong red autumn foliage; winterberry berries sit closely along the stems at leaf joints.

Winterberry refers to its persistent winter fruit, while the Latin species name verticillata means whorled, referring to the arrangement of fruits around the stems.

Propagation. Take softwood cuttings in early summer or semi-ripe cuttings later in summer; use rooting hormone and keep humid until rooted. Rooted suckers can sometimes be separated during dormancy. Seed germination is slow, and seedlings vary in sex and do not reliably reproduce named cultivars.

Accepted botanical name

Ilex verticillata

In the US and Canada

Native in Canada, the lower 48 states and St. Pierre and Miquelon.

Native range

Alabama, Arkansas, Connecticut, Delaware, District of Columbia, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky and Louisiana.

Measured

Soil pH 4.5 to 7.5. Average height 250 cm.

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