American holly
Ilex opaca
also called christmas holly
The native Christmas holly: a broad pyramid of matte spined evergreen leaves hung with red berries from November into March, and shelter for every songbird in the yard.
- Type
- Tree · Perennial
- Botanical family
- Mixed / other
- Foliage color
- Green
- Flower color
- Red
- Sunlight
- Sun or part shade; berries best with more light
- Watering
- Moderate
- Soil
- Acidic, moist, well-drained
- Feeding
- Gentle all-organic
- USDA zones
- 5b–9b
- Frost tolerant
- Yes
- Plant out
- 14 days before the last spring frost
- Plant spacing
- 16 ft 5 in
- In-row spacing
- 13 ft 1 in
- Between rows
- 23 ft
- Square-foot density
- Not suited to SFG
- Root system
- Woody, shallow and far-reaching
- Working depth
- 12–24 in
- Can reach
- 4 ft down where the soil allows
- Spread
- 39–59 ft across, about 2–3× the width of the plant
Almost all of a tree’s roots are in the top two feet of soil, where the air is, and they run out well past the branch tips. The deep taproot most people picture belongs to the seedling; the tree grows out of it and spends the rest of its life spreading sideways instead.
The habit is American holly’s own; the figures are what that habit usually comes to at this size, not a measurement of this species. Roots follow the soil either way: a compacted pan, a high water table or heavy clay stops them well short of any of it, and deep open ground lets them go further.
- Cats and dogs
- Recorded toxic
Recorded as toxic to cats and dogs by ASPCA.
- When
- Cut berried branches for the house in early December; that cutting is also the year's pruning.
- What to look for
- Berries fully red and the birds not yet desperate: early winter, before the cedar waxwings arrive in force.
- How to harvest
- Cut sprays back to a side shoot so the wound hides, taking them evenly around the tree. Wear gloves; the spines mean it.
- How often
- One December cutting. Formal shaping, if wanted, happens with the same cuts.
- Storing the crop
- Cut holly holds a week or two in a cool room, longer outdoors in wreaths. The berries are for birds and decoration only — mildly toxic to people and pets.
Beneficial predators that hunt this plant's pests — grow their favourite flowers nearby to recruit them. companion plant
- Hoverfly SyrphidaeHunts Scale insects
Bee-mimicking flies whose legless larvae graze aphid colonies clean while the adults pollinate. A ribbon of shallow, nectar-rich flowers kept in bloom all season recruits wave after wave of them.
- Ladybird (lady beetle) CoccinellidaeHunts Scale insects
The gardener’s favorite ally: adults and their alligator-shaped larvae each eat thousands of aphids, plus scale, mealybugs, and other soft-bodied sap-suckers. Grow flat, open flowers for the adults and never spray a colony that ladybird larvae are already working.
- Parasitic wasps Braconidae & TrichogrammaHunts Leaf miners
Tiny, stingless wasps that lay eggs in or on caterpillars, aphids, and moth eggs — the white cocoons riding a hornworm are their calling card, so leave that caterpillar be. Umbel flowers with shallow nectar keep the adults fuelled.
Hollies are male or female, and only females berry, only when a male grows within bee range. One male pollinates a dozen females, so buy named cultivars and read the tag, or the tree you wait a decade on will never carry a single berry.
The Cottage Garden Companion — the gardener's herbarium at cottagegardencompanion.com