Shrub · Aquifoliaceae
Inkberry Holly
Ilex glabra
A forgiving native shrub that shrugs off 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
If you are new to shrubs, inkberry holly is a kind place to start. It is a slow, steady evergreen from eastern North America, named for the black berries that once gave a country dye. Its leaves are smooth and small rather than the prickly ones on the English hollies most people imagine, so it is comfortable to grow right beside a path, and it settles in as a low, year-round green backbone for a bed or a hedge.
The reason it suits a beginner so well is how much it forgives. It is happy in acidic, wet ground where fussier shrubs would sulk, it holds up through winters near -29°F (-34°C), and it accepts full sun or part shade without complaint. Its one quirk is habit: the wild plant spreads by suckers and can thin out at the base as it ages, which is exactly why many gardeners choose one of the tidier named cultivars and save themselves the fuss.
It comes in male and female plants, so a lone shrub will not fruit, and you simply pair it with a male nearby if you want the berries. Those berries feed birds deep into winter and the flowers bring in honeybees, which is part of why it turns up on so many native-plant lists. Plant it once, and it will ask very little of you.
Care
The short version: give it acidic, evenly moist soil in full sun to part shade, feed it lightly, and hand it an easy spring prune now and then so an older plant does not go bare at the base.
Light
Inkberry is happy in full sun to part shade, and the more sun it gets, the fuller and denser it grows for you. In deep shade it turns thin and leggy and loses its shape, so give it as much light as your spot allows and it will reward you.
Water
This shrub likes its soil consistently moist, and it even copes with wet or boggy ground that would rot most plants, so a soggy corner is no problem. It becomes moderately drought tolerant once established, but while it is young it 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 handles wet sites with ease, but neutral to alkaline ground leads straight to yellow leaves, so keep it away from limed soil and you will avoid the trouble.
Temperature
Inkberry is genuinely tough in the cold, taking lows near -29°F (-34°C) and summer heat up to about 100°F (38°C). That range covers most temperate gardens, so you can leave the winter protection in the shed.
Humidity
Ordinary outdoor humidity suits it just fine, so there is no number to fuss over. As a native of damp woods and bogs, it cares far more about moisture at its roots than about the air around it.
Feeding
It hardly needs feeding at all, which makes life easy. A single dose of balanced or acidifying holly or azalea fertilizer in early spring is plenty, and an acidifying type has the bonus of helping hold the soil on the sour side it prefers.
Pruning
Most years it asks for very little, so do not feel you have to fuss. Prune to shape in early spring just before new growth starts, and if an older plant goes bare and woody at the base, cut it back hard to bring fresh, dense growth from low down.
Repotting
Grown in a container, inkberry seldom needs moving. Pot it up only when the roots circle the pot, poke out the drainage holes, or water rushes straight through, since those are the plant's way of telling you it has outgrown its home.
Size & spacing
Expect a grown shrub of 5 to 10 feet (1.5 to 3 m) tall, spreading 5 to 8 feet (152 to 244 cm) wide. Space plants by that mature width so a hedge knits together nicely while each shrub still gets the airflow it wants.
When to plant
Inkberry is a hardy shrub, so there is no anxious planting window to catch. Settle new plants into the ground in spring or fall while the soil is workable and damp, look for greenish-white flowers in late spring, and enjoy the black drupes as they ripen in fall and cling on 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 keeps out of trouble most years, so try not to worry. The handful of problems it does meet turn up on the leaves or in the shape of the plant, and each one has a clear cause you can act on. Find what matches below, then treat the root of it rather than the symptom, and the plant will come right.
Pale leaves that keep their green veins
Take heart, because this is iron chlorosis and it is fixable. It shows up when the soil has crept out of the acidic range your inkberry loves, and once the pH rises toward neutral the roots simply cannot take up the iron that is sitting right there. Check the soil, gently work in some acidic organic matter to ease the pH back toward 5.0 to 6.0, and leave the lime out.
Fix:
- Acidify soil and lower pH toward 5.0-6.0
- Apply iron/chelated micronutrients per label
- Improve organic matter and avoid liming
Bare stems below with leaves only up top
Please do not read this as failure on your part. Older inkberry naturally goes thin and open near the ground, and a shady spot only hurries it along, so this is simply the wild plant showing its years. You can renewal-prune in early spring to coax fresh growth low down, give it a sunnier home, or start again with a naturally neat cultivar such as Shamrock, Compacta, or Gem Box, and any of those will put things right.
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
Trails, blotches, or fine speckles across the leaves
None of this will harm a healthy inkberry, so you can relax while you sort it out. Winding trails or blotches mean a leaf miner is tunneling inside the leaf, fine pale speckling points to spider mites, and small waxy bumps on stems and leaves are scale. Simply pick off the worst leaves, treat mites or scale with a suitable horticultural control, and keep the plant well watered so it can shake off the damage on its own.
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, so there is no need for alarm, though it is not something to eat. As with other hollies, the leaves and berries hold saponins and related compounds that unsettle the stomach if swallowed, and the berries are the main concern. A nibble means a sore tummy rather than an emergency, but it is still wise to keep the berries and trimmings away from pets and small children.
Toxic to
Cats · Dogs · Horses · Rabbits · Livestock · People
Safe for
Birds
Cats Mild
If your cat mouths the leaves or berries, expect some drooling followed by vomiting and perhaps a little diarrhea. For a day it may seem quiet and uninterested in food. The berries are the part most likely to set this off, so those are the ones to watch.
Dogs Mild
A dog that swallows a mouthful of berries or foliage tends to react much as a cat does, with a queasy stomach, some vomiting, and loose stools. The saponins and the eaten leaves are what do the irritating. The good news is that it stays mild and usually settles on its own.
Horses Mild
Horses seldom take an interest in inkberry, but one that does graze the foliage can turn colicky and dull. To be safe, simply keep any clippings out of the paddock.
Rabbits Mild
A rabbit's gut is easily upset by the leaves and berries, leaving it quiet and off its feed, so keep these out of the hutch and the run and you will have nothing to fret about.
Livestock Mild
Goats, sheep, and cattle can end up with a sour stomach from the saponins if they browse the foliage, though a serious poisoning is uncommon. Fencing the shrubs off or clearing away the trimmings keeps everyone comfortable.
People Caution
The berries and leaves are mildly toxic to people and should not be eaten, and the berries matter most, especially with small children who might find them tempting. A few swallowed berries usually bring on vomiting and diarrhea rather than anything worrying. Keep them out of reach and wash your hands after pruning and you are in good shape.
Birds Safe
You can feel good about this one, since birds eat the drupes right through winter with no harm at all, and feeding them is part of why the shrub is planted. What unsettles a pet's stomach is simply a meal 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 over time, so most gardeners reach for a named cultivar bred to stay neat, which takes the worry out of it. Here are the ones worth knowing.
Shamrock
A neat, mounded pick that holds its rounded shape and stays far tidier at the base than the wild species.
Compacta
A female selection that grows denser and lower than the species, so it fills right in without going bare at the ankles.
Gem Box
A small, rounded grower with fine dark leaves that makes a forgiving stand-in for boxwood.
Nigra
Loved for rich green foliage that keeps its color beautifully as the seasons turn.
How to propagate
You can make more inkberry from cuttings, from its own suckers, or from seed, and the one you choose comes down to how patient you feel and whether you mind which plant you end up with. Any of them can work for you.
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 grow inkberry, and the only one that keeps a named cultivar true to type, so you know just what you are getting. Snip semi-hardwood or softwood tips from the branch ends in early to mid summer, around June or July. Give them time, since they root over several weeks to a few months and then want a season or more to settle in.
DivisionEasy
Early spring · One growing season
Inkberry sends up rooted suckers around the parent, and these are a gift to a new grower because you can slice one away and replant it. Lift them in early spring, and they need only about one growing season to find their feet. If you simply want more of a shrub you already love, this is the gentlest route.
SeedDemanding
After cleaning ripe fruit · Slow; seed has dormancy and can be slow to germinate
Seed is the patient grower's path, so save it for when you are in no hurry. Clean the seed from ripe fruit before you sow, then wait, because it carries a built-in dormancy and comes up slowly. The seedlings arrive as a mix of male and female, which means you will want at least one male among them for any female to fruit.
Myths
A single inkberry, planted alone, will still reward you with black berries.
Inkberry is dioecious, so each plant is either male or female. The black drupes form only on female plants, and even then they set fruit only when a male grows near enough to pollinate them. Give a female a male companion nearby, or a solo shrub will never berry.