Shrub · Aquifoliaceae
Inkberry Holly
Ilex glabra
A smooth-leaved native shrub that takes wet ground, hard winters, and shade and stays green all year.
Full sun
Every 3–7 days
USDA 4–9
5–10 ft · 1.5–3 m
Overview
Inkberry holly is a slow-growing evergreen shrub of eastern North America, named for the small black berries whose juice once served as a country dye. Up close its leaves are the surprise: smooth-edged, small, and glossy, without a single spine of the sort the English hollies carry, and dark green enough to read almost black in low light. The stems hold that fine foliage year round, so the shrub keeps its deep color even through the cold months.
In late spring, from May to June, it opens tiny greenish-white flowers tucked among the leaves, easy to miss until the bees find them. By September the pollinated female plants set the fruit that names the plant, round black drupes that sit against the dark leaves and hold on through winter. The frame beneath is slow and woody, and in the wild species the lower stems tend to bare over the years while the leaves crowd toward the top.
It grows in acidic, wet ground and shrugs off winters near -29°F (-34°C), taking full sun or part shade. The species is dioecious, so a female needs a male growing nearby before those black berries can form. The fruit feeds birds deep into winter and the spring flowers draw honeybees, which is part of why the shrub turns up on so many native-plant lists.
Care
The short version: inkberry wants acidic, consistently moist soil in full sun to part shade, little feeding, and an occasional spring prune to keep the small, glossy leaves reaching low rather than baring at the base.
Light
Inkberry takes full sun to part shade, and more sun packs the small glossy leaves in denser and fuller. In deep shade the stems stretch and thin, the foliage grows sparse, and the shrub loses its rounded outline, so give it as much light as the spot allows.
Water
This shrub likes its soil consistently moist and even holds its deep green in wet to boggy ground that would rot most plants. It runs moderately drought tolerant once established, but a young plant needs steady water, roughly every 3 to 7 days, until the roots take hold.
Soil
Plant it in acidic, organically rich soil, ideally a pH of 5.0 to 6.0. It adapts to clay or sand and copes with wet sites, but neutral to alkaline ground drains the green from the leaves and turns them yellow, so steer clear of limed soil.
Temperature
Inkberry is genuinely cold-hardy, holding its evergreen leaves through lows near -29°F (-34°C) and taking summer heat up to about 100°F (38°C). That range covers most temperate gardens without any winter protection.
Humidity
Ordinary outdoor humidity suits it, so there is no number to manage. As a native of damp woods and bogs, it cares far more about moisture at the roots than about the air around its leaves.
Feeding
It barely needs feeding. A single dose of balanced or acidifying holly or azalea fertilizer in early spring is plenty, and an acidifying type also helps hold the soil on the sour side that keeps the foliage deep green.
Pruning
Most years it asks for very little. Prune to shape in early spring just before new growth starts, and when an older plant goes bare and woody at the base, cut it back hard to force fresh, densely leaved growth from low down.
Repotting
Grown in a container, inkberry rarely needs moving. Pot it up only when the roots circle the pot, push out the drainage holes, or water races straight through, all signs the plant has outgrown its home.
Size & spacing
A mature shrub stands 5 to 10 feet (1.5 to 3 m) tall and spreads 5 to 8 feet (152 to 244 cm) wide, a rounded mass of small dark leaves. Space plants by that mature width so a hedge closes into a solid green wall while each shrub keeps its airflow.
When to plant
Inkberry is a hardy shrub with no real planting season to wait out. New plants go in the ground in spring or fall while the soil is workable and moist, the tiny greenish-white flowers open in late spring, and the round black drupes ripen in fall and cling to the dark stems through winter.
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: May to June (greenish-white flowers); black drupes mature September and persist into winter
Hardiness
USDA hardiness zones: 4–9
Temperature: down to -34°C
Troubleshooting
Inkberry stays out of trouble most years. What little goes wrong shows itself right on the plant, in the color of the leaves or the shape of the stems, and each sign has a clear cause. Match what you see below, then treat the reason behind it rather than the mark on the surface.
Yellow leaf blades laced with green veins
When the blade of each leaf pales to yellow while a fine network of veins stays green, the plant is showing iron chlorosis. On inkberry that pattern traces to soil that has slipped out of its acidic range, so as the pH climbs toward neutral the roots lose their hold on iron. A soil test, acidic organic matter worked in to bring the reading back toward 5.0 to 6.0, and no lime return the leaves to an even, deep green.
Fix:
- Acidify soil and lower pH toward 5.0-6.0
- Apply iron/chelated micronutrients per label
- Improve organic matter and avoid liming
Bare woody stems below a leafy crown
The lower stems stand bare and woody while the small evergreen leaves crowd toward the top, and this open, leggy frame is the natural aging habit of the species, hurried along by shade rather than caused by any disease. A renewal prune in early spring wakes fresh leaves low on the stems, brighter light keeps them there, and the dense, fine-leaved cultivars Shamrock, Compacta, and Gem Box carry their foliage close to the ground.
Fix:
- Renewal-prune in early spring to encourage dense basal growth
- Site in fuller sun
- Choose compact cultivars such as 'Shamrock', 'Compacta', or Gem Box
Pale trails and speckles across the leaf surface
Pale serpentine trails or blotches carved into the green blade mark a leaf miner feeding between the leaf surfaces, a fine dusting of pale stipple points to spider mites, and small waxy bumps clinging to stems and leaves are scale. None of it scars a healthy inkberry for long. The worst-marked leaves come off, a suitable horticultural control clears mites or scale, and steady water lets fresh, unblemished leaves fill back in.
Fix:
- Remove and destroy heavily infested leaves
- Monitor and treat mites/scale with appropriate horticultural controls per label
- Maintain plant vigor with proper water and soil
Toxicity
Inkberry is only mildly toxic, but it is not harmless. Like other hollies, its smooth leaves and small black berries hold saponins and related compounds that upset the stomach if eaten, and the glossy berries are the main worry. A nibble means an upset gut rather than an emergency, yet the berries and trimmings still belong out of reach of pets and small children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · People
Safe for
Birds
Cats Mild
A cat that bites into the smooth leaves or the small black berries usually drools, then vomits, with some diarrhea to follow, and looks dull and off its food for a day. The berries carry most of the irritant, so they are the part most likely to cause the upset.
Dogs Mild
Dogs react much as cats do, with an upset stomach, vomiting, and loose stools after a mouthful of the dark berries or the glossy foliage. The saponins and the chewed leaves do the irritating, and the signs stay mild and clear on their own.
Horses Mild
Horses rarely touch inkberry, but one that grazes the small leathery leaves can turn colicky and dull. Keep clippings out of the paddock to be safe.
Rabbits Mild
The leaves and berries can upset a rabbit's gut and leave it quiet and off its feed, so neither the foliage nor the black fruit belongs in the hutch or the run.
Livestock Mild
Grazing animals such as goats, sheep, and cattle may get a sour stomach from the saponins in the leaves, though serious poisoning is uncommon. Fence the shrubs off or clear the trimmings rather than let stock browse the foliage.
People Caution
For people the black berries and the leaves are mildly toxic and are not to be eaten, with the glossy berries the bigger worry, above all for small children drawn to their color. A few swallowed berries tend to bring vomiting and diarrhea rather than anything dangerous. Keep them out of reach and wash up after pruning.
Birds Safe
Birds work through the small black drupes all winter without harm, and the shrub is grown partly to feed them. The very fruit that turns a pet's stomach is winter food for a songbird.
Keep berries and trimmings away from pets and children; wash hands after handling.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
Poison Control: (800) 222-1222
Canada
Poison Centres: 1-844-764-7669
Varieties
The wild species can go leggy and bare at the base over time, so most gardeners plant a named cultivar bred to hold its leaves low and dense. These are the ones worth knowing.
Shamrock
A compact, mounded selection that keeps a rounded, close-knit outline and stays far less leggy than the wild species.
Compacta
A female cultivar that grows denser and lower than the species, clothing its stems in leaves right down to the base.
Gem Box
A small, rounded grower whose fine, dark leaves recall boxwood, for which it stands in as a tougher substitute.
Nigra
A selection whose deep green leaves hold their rich color through the changing seasons.
How to propagate
You can raise more inkberry from cuttings, from its own rooted suckers, or from the seed inside its black fruit, and the route you pick depends on how patient you are and whether you care which plant you end up with.
Stem cuttingsModerate
Early to mid summer (June-July) · Several weeks to months to root, then a season or more to establish
Cuttings are the usual way to raise inkberry, and the only route that keeps a named cultivar true to type. The tips taken are semi-hardwood or softwood shoots from the ends of the branches, cut in early to mid summer, around June or July. They root over several weeks to a few months, then settle in over a season or more.
DivisionEasy
Early spring · One growing season
Inkberry throws up rooted suckers around the parent, slender shoots already anchored by their own roots that can be sliced off and replanted. Lifted in early spring, they take about one growing season to establish. It is the simplest way to gain more of a shrub already in the ground.
SeedDemanding
After cleaning ripe fruit · Slow; seed has dormancy and can be slow to germinate
Seed is the slowest path. The seed is cleaned out of the ripe black fruit before sowing, and a built-in dormancy leaves it slow to germinate. The seedlings come up as a mix of male and female, so a batch needs at least one male among them for the females to fruit.
Myths
A single inkberry on its own will still ripen a crop of black berries.
Inkberry is dioecious, so each plant is either male or female. The small black drupes form on the female plants alone, and only once a male grows close enough to pollinate them. Without a male nearby, a lone shrub sets no fruit at all.