American Holly

Ilex opaca

Native to:
United States

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Taxonomy

Division:
Magnoliophyta | - Flowering plants
Family:
Aquifoliaceae
Genus:
Ilex
Species:
Ilex opaca
USDA Symbol:
ILOP

Growth Characteristics

Life Cycle:
Perennial
Growth Habit:
Shrub , Tree
Height:
1500 cm
Light Requirements:
Full Sun,Part Shade,Shade
Drought Tolerance:
Medium
Bloom Months:
apr,may,jun
Bloom Colors:
white, cream

Wildlife Benefits

Bees:
★☆☆☆☆ Documented bee visitation (GBIF)
Caterpillars:
★★☆☆☆ Recorded caterpillar host plant (HOSTS Database)

Keystone Species Ranking

Caterpillar Keystone:
★★★★☆ Butterfly & moth species supported by this genus (NWF)
Pollen Specialist Bee Keystone:
★☆☆☆☆ Native pollen specialist bee species supported by this genus (NWF)

Host Plant for Caterpillars

Ailanthus silkmoth (Samia cynthia), Alfalfa Looper (Autographa californica), Fall webworm (Hyphantria cunea), Gypsy moth (Lymantria dispar), Metaxaglaea violacea, orange tortrix moth (Argyrotaenia citrana), Unicorn caterpillar moth (Schizura unicornis), Walker’s Atlas Moth (Samia walkeri), White-marked Tussock Moth (Orgyia leucostigma), Henry's Elfin (Incisalia henrici), Holly Blue (Celastrina argiolus), Striped Hairstreak (Satyrium liparops)

Reported Fauna Sightings

Bees: Eastern Carpenter Bee (Xylocopa virginica), ⚠️Western honey bee (Apis mellifera) Moths:Episemasia solitaria, Ilexia intractata, Psyche casta, Rhopobota Lederer Butterflies:Azure sp. (Celastrina Tutt), Henry's Elfin (Callophrys henrici)

Garden & Ecology Notes

Wildlife Value:
birds, small mammals
Deer Resistant:
Yes
Salt Tolerant:
Yes

Soil Requirements

Soil Type:
rich, well-drained loamy soil
pH:
5.0 - 6.5 (acidic to slightly acidic)
Drainage:
excellent drainage required
Moisture:
consistently moist
Notes:
Prefers organic matter-rich soils in native forests

Propagation & Germination

Stratification:
Warm then cold/moist stratification (double dormancy) — 60–120 days
Germination Time:
30–365 days
Notes:
Seeds exhibit double dormancy requiring warm stratification followed by cold stratification. Germination may take 2-3 years in nature.

The above propagation data sourced from Claude AI

Pre-treatment: Holly seeds exhibit deep dormancy and do not germinate until the second year. After cleaning, seeds are planted in late September using a Love seeder set at 3rd gear at 6 setting into prepared field beds.

Establishment: Seeds are purchased from local people who collect within a 50 mile radius of the nursery. American holly is dioecious; female plants bear red to red-orange fruits during fall months. American holly is found from Massachusetts to Florida east to Texas and Missouri. Seed sources are from south central Missouri.

Source: npn.rngr.net

ORGHPS Germination Guide: Expose to fluctuating outdoor winter temps incl. freezing for 3 months. Increase light/temp in spring.

Source: Ontario Rock Garden & Hardy Plant Society