

English Holly Ilex aquifolium
English Holly is an introduced perennial tree, found in Canada, Hawaii, and the lower 48 states. It grows to 21 ft and blooms May – Jun.
More about this plant
Ilex aquifolium, the holly, common holly, English holly, European holly, or occasionally Christmas holly, is a species of flowering plant in the family Aquifoliaceae, native to western and southern Europe, northwest Africa, and southwest Asia. It is regarded as the type species of the genus Ilex, which by association is also called holly. It is an evergreen tree or shrub found, for example, in shady areas of forests of oak and in beech hedges. In the British Isles it is one of very few native hardwood evergreen trees. It has a great capacity to adapt to different conditions and is a pioneer species that repopulates the margins of forests or clearcuts. Wikipedia →
English Holly is flagged invasive in the U.S. These natives fill a similar niche — same growth habit, bloom season, height, and region — so you keep the look and feed local wildlife instead of spreading a problem.
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 8 derived from its U.S. range
- Drought tolerance
- Moderate
- Shade tolerance
- High
- Wet-soil tolerance
- Low waterlogging
- Height
- 21 ft
- Lifespan
- Perennial
- Foliage
- Evergreen broadleaf
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~39 caterpillar species
Ilex supports ~39 caterpillar species.
Native butterfly & moth caterpillars are the base of the terrestrial food web — most songbirds rear their young almost entirely on them. As a host for native Lepidoptera this is a strong genus.
Recorded feeding on Ilex in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees specialist-bee host · 30 bee visitors
Specialist native bees depend on it.
Some native bees are pollen specialists (oligolectic) — they raise young only on pollen from particular plant genera. Ilex is a recorded specialist-bee host, so losing it can mean losing the bee that relies on it.
30 native & managed bee species are documented visiting English Holly — the 12 most-recorded:
Wildlife & visitors 6 birds · 5 nectaring
Open records of who else uses English Holly — a generalist food-web signal, kept separate from the keystone Ecological Value.
Recorded eaten by 6 birds species (fruit, seed, browse):
5 adult butterfly & moth species are recorded nectaring at its flowers:
How we know this (3) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
A recorded categorical fact: each species is tagged C3 (standard), C4 (heat/water-efficient) or CAM (succulent, night-time CO₂ uptake) — or a facultative combination. We only show a trait card for the noteworthy C4/CAM cases; C3 is the unremarkable majority, kept in the data but not surfaced as a card.
We take the plant’s U.S. county range and look up each county’s long-term climate, then summarise: native rainfall = the median annual rainfall across its counties; heat tolerance = the warm end (90th percentile) of average temperature across its range (mirroring how our cold-hardiness floor uses an extreme). Counties + medians blunt the roadside/observer bias that makes point-level climate unreliable. Needs at least five placeable counties.
Honest limits: A realized, sampling-biased niche (where it has been recorded, not its physiological optimum), and county climate is coarse — large Western counties span deserts and mountains. Derived guide, never a measured fact.
Sources for this entry (27) Open & cited
Cite this page Open data, please attribute
PlantKey’s data is open under CC BY-SA 4.0 — free to reuse and adapt, with attribution and the same licence. Photos keep their own per-image licence + credit (see Sources above).
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