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Aquifoliaceae family

Japanese Holly Ilex crenata

Japanese Holly is an introduced perennial tree, found in the lower 48 states. It grows to 10 ft and blooms Apr in full sun, with black fruit.

More about this plant

Ilex crenata, also known as Japanese holly or box-leaved holly, is a species of flowering plant in the family Aquifoliaceae, native to East and Southeast Asia. Wikipedia →

Growing & care

USDA PLANTS · TRY
Conditions
Sources · Conditions
USDA PLANTS — Sun · Soil & moisture
USDA — SoilPH — Soil pH
USDA PLANTS (DwCA, Zenodo 17903503) — Fertility Requirement / Soil Adaptation — Fertility need · Adapts to
USDA — Temp-Min °F — Hardiness
Sun
Full sun
Soil & moisture
Medium moisture
Soil pH
4.5–5.5
Fertility need
Medium
Adapts to
Coarse (sandy), Medium (loam)
Hardiness
USDA zone 6+
Size & form
Sources · Size & form
USDA PLANTS (DwCA, Zenodo 17903503) — Height, Mature — Height
Derived (allometric) — width = height × functional-class crown ratio fit on USDA Urban Tree DB · Tallo; method per Jucker et al. 2022, Pretzsch et al. 2015 — Mature width
USDA PLANTS (DwCA, Zenodo 17903503) — Planting Density (per acre) — Spacing
USDA PLANTS (DwCA, Zenodo 17903503) — Growth Rate / Spread / Growth Form / Lifespan / Active Growth Period / Seed Period — Spread · Growth rate · Growth form · Active growth
USDA PLANTS — Lifespan
TRY Plant Trait Database (CC BY 4.0) · USDA PLANTS — Foliage
USDA PLANTS (DwCA, Zenodo 17903503) — Fruit/Seed Color / Fruit Persistence — Fruit
Lifespan: USDA’s lifespan scale for trees: short = under ~100 years · moderate = 100–250 · long = over 250. Balsam fir and other short-lived conifers are genuinely short for a tree, not short like an annual.
Height
10 ft
Mature width
~ 8 ft wide DERIVED derived estimate — open-grown crown allometry (height × growth-form ratio); not a measurement
Spacing
5–6 ft apart from USDA planting density
Spread
None — clumping
Growth rate
Slow
Growth form
Multiple stems
Lifespan
Perennial · long-lived
Foliage
Evergreen broadleaf · fine texture
Active growth
Spring & summer
Fruit
Black
In the garden
Sources · In the garden
USDA PLANTS (DwCA, Zenodo 17903503) — Propagation Method / Commercial Availability — Propagate by · In the trade
USDA PLANTS (DwCA, Zenodo 17903503) — Germination (cold stratification) — Seed starting
USDA PLANTS — Seed Period — Seeds ripen
USDA PLANTS (DwCA, Zenodo 17903503) — Foliage Texture / Browse Palatability / Resprout — Resprouts if cut
Propagate by
Cuttings, Bare root, Container
Seed starting
Needs cold stratification a cold-moist spell before it germinates
Seeds ripen
Spring – Summer seed-collection / harvest window
In the trade
Routinely available
Resprouts if cut
Yes regrows after top-kill
Shrub layer — Sits in the shrub of a layered food forest or polyculture.Open guide →
derived roles
AI = read by an AI vision model · DERIVED = a computed estimate, not a direct measurement. The “How we know this” section below details each.
The garden year bloom → fruit → fall colour
J
F
M
A
M
J
J
A
S
O
N
D
Bloom
Fruit
Bloom (the flower's colour) Ripe fruit
Bloom · Apr — USDA PLANTS (DwCA, Zenodo 17903503) — BloomPeriod
Fruit · approximate season (USDA Seed Period), clamped to after bloom
When to sow · for your area

Sow timing keys off your local last- and first-frost dates.

Species characteristics from USDA PLANTS (public domain) + TRY (CC BY) — general guidance, not a guarantee for your exact site. Deer "browsing" is documented palatability, not a deer-proof claim.

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:

Oiketicus abbotii · Abbot's Bagworm Moth ✦ Thyridopteryx ephemeraeformis · Evergreen Bagworm Moth ✦ Acharia stimulea · Saddleback Caterpillar Moth Apatelodes torrefacta · Spotted Apatelodes Argyrotaenia citrana · leafroller moth Argyrotaenia velutinana · Red-Banded Leafroller
+ 8 more species →
Autographa californica · Alfalfa Looper Moth Automeris io · giant silk moth Bucculatrix ilecella · ribbed cocoon-maker moth Celastrina argiolus · Holly Blue Cepphis armataria · Scallop Moth Choristoneura rosaceana · Oblique-Banded Leafroller Cicinnus melsheimeri · Melsheimer's Sack-Bearer Moth Ditula angustiorana · Red-Barred Tortrix
Keystone count (genus-level) from Warren II 2026 (CC0) · Tallamy host-use records. Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0). ✦ = recorded on this exact species.
✦ Bees specialist-bee host · 3 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.

Xerces pollinator conservation →

3 native & managed bee species are documented visiting Japanese Holly :

Apis mellifera · Honey Bee Colletes thoracicus · cellophane bee Xylocopa virginica · Eastern Carpenter Bee
Specialist hosts from Smith et al. 2024. Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI →
Wildlife & visitors 1 nectaring

Open records of who else uses Japanese Holly — a generalist food-web signal, kept separate from the keystone Ecological Value.

1 adult butterfly & moth species is recorded nectaring at its flowers:

Satyrium favonius · Oak Hairstreak
Interaction records (observations, not exhaustive) from GloBI → (CC0). Counts are distinct species; names are the most-recorded. Common names from Wikidata (CC0).
Species thumbnails re-hosted from iNaturalist — Creative Commons, credited per image (hover for credit). Click any species to see it on iNaturalist. Not exhaustive; many taxa have no openly-licensed photo yet.
How we know this (3) Methods & honest limits
Photosynthesis Direct fact

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.

Kattge, J. et al. TRY plant trait database — Categorical Traits Dataset (2012).
Climate niche (heat tolerance & native rainfall) Derived

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.

Realized-niche / climate-envelope approach (Pearson & Dawson 2003; Soberón 2007). Climate: NOAA NCEI nClimDiv county normals (1991–2020).
Mature width Derived

For woody plants that have a height but no measured crown, we estimate width = height × a crown-to-height ratio fit for that plant’s form (conifers narrower than broadleaf trees, shrubs widest), calibrated on our measured open-grown crowns and capped at the largest one ever measured. A measured crown always wins; herbaceous plants get nothing (no anchor).

Honest limits: A coarse class-median estimate for garden-scale spacing, not a measurement; woody single/multi-stem forms only.

Allometric basis: Jucker et al. 2022 (Tallo); Pretzsch et al. 2015; McPherson et al. 2016 (USDA Urban Tree DB).
Derived values are computed from open data by a published method — labelled, cited, and never shown as a direct observation. Full methodology →
Sources for this entry (34) Open & cited
[01] Scientific name & family — USDA PLANTS (DwCA, Zenodo 17903503)
[02] Growth habit & duration — USDA PLANTS (DwCA, Zenodo 17903503)
[03] Native status & distribution — USDA PLANTS (DwCA, Zenodo 17903503)
[04] Common name — USDA PLANTS (via GBIF)
[18] Invasive / introduced status — US-RIIS v2.0 (USGS)
[20] Description — Wikipedia (CC BY-SA)
[21] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts · Smith et al. 2024 (CC BY)
[23] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[24] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[25] Climate niche — Derived — realized climate niche from U.S. county occurrences (GBIF) × NOAA NCEI county climate normals 1991–2020 (public domain)
[26] Wildlife & visitors — GloBI — Global Biotic Interactions (CC0)
[28] Rooting depth — Fan et al. 2017 (Dryad, CC0)
[31] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[32] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[33] Caterpillar species — NHM HOSTS (CC0)
[34] County range — GBIF Open Data — open-licensed occurrences (CC0/CC-BY) → county
Spot an error or have a better photo? Every field links to its source, and the whole dataset is open.
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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