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iNaturalist — CC, credited & licensed per image
Liliaceae family

Tapertip Onion Allium acuminatum

Native
Deer favourite — Rated highly palatable to browsing deer — so where deer are around, expect this one to get nibbled. It's a documented preference, not a certainty: pressure swings with the place and season, and a fenced or low-deer yard may be untouched.

Tapertip Onion is a perennial wildflower native to Canada and the lower 48 states. It grows to 1 ft and blooms Jul in part shade – shade, with black fruit.

More about this plant

Allium acuminatum, also known as the tapertip onion or Hooker's onion, is a species in the genus Allium native to North America. 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
Part shade – shade
Soil & moisture
Low moisture
Soil pH
6–8
Fertility need
Low
Adapts to
Coarse (sandy), Medium (loam)
Hardiness
USDA zone 5+
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
McKenzie et al. 2025 — community-science image analysis (MIT) — Flower colour
Height
1 ft
Mature width
~ 1 ft wide DERIVED derived estimate — open-grown crown allometry (height × growth-form ratio); not a measurement
Spacing
2–3 ft apart from USDA planting density
Spread
None — clumping
Growth rate
Rapid
Growth form
Multiple stems
Lifespan
Perennial · short-lived
Foliage
Broadleaf · fine texture
Active growth
Spring & summer
Fruit
Black
Flower colour
Purple AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
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 — Deer browsing · Resprouts if cut
Propagate by
Seed, Container, Bulbs
Seed starting
Needs cold stratification a cold-moist spell before it germinates
Seeds ripen
Summer – Autumn seed-collection / harvest window
In the trade
Contract growing only
Deer browsing
High browsed readily
Resprouts if cut
No
Herb layer — Sits in the herb 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
Bloom (the flower's colour)
Bloom · Jul — USDA PLANTS (DwCA, Zenodo 17903503) — BloomPeriod
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 ~21 caterpillar species

Allium supports ~21 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 moderate genus.

Recorded feeding on Allium in North America, including:

Actebia fennica · owlet moth Aglossa caprealis · Meal Moth Agrotis gladiaria · Swordsman Dart Agrotis ipsilon · Dark Sword-Grass Agrotis malefida · Rascal Dart Agrotis orthogonia · Pale Western Cutworm
+ 8 more species →
Archips argyrospila · Fruit-Tree Leafroller Moth Autographa californica · Alfalfa Looper Moth Cadra cautella · Fig-Moth Cadra figulilella · snout moth Cryptoblabes gnidiella · snout moth Discestra trifolii · owlet moth Ephestia elutella · snout moth Estigmene acrea · Salt Marsh Moth
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).
✦ Bees 43 bee visitors
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI → · ✦ = pollen-specialist bee (Smith et al. 2024)
Wildlife & visitors 3 nectaring

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

3 adult butterfly & moth species are recorded nectaring at its flowers:

Argynnis callippe Pontia beckerii · Becker's White Erynnis propertius · Propertius Duskywing
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 (4) 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).
Flower colour Derived

McKenzie et al. assigned each species a flower colour with a GPT-4V vision model over iNaturalist photos. We use the confident tier plus a separately-labelled lower-confidence top-up (mostly inconspicuous green/brown flowers), and render it as a small tint — never as an asserted fact, and kept out of the written synopsis.

Honest limits: AI image inference (~87% expert agreement on the confident tier); a decorative, confidence-tiered indicator, not a measured trait.

McKenzie, P., Berardi, A.E., Hopkins, R. (2025). flower_color_phenology (MIT).
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 (35) 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 — USDA PLANTS (DwCA, Zenodo 17903503) — native status
[20] Description — Wikipedia (CC BY-SA)
[21] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts
[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)
[31] Bee specialists — Smith et al. 2024 (Zenodo, CC BY 4.0)
[32] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[33] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[34] Caterpillar species — NHM HOSTS (CC0)
[35] 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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