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Asteraceae family

Clasping Arnica Arnica amplexicaulis

Native
Deer-resistant — Low palatability to browsing deer. Usually passed over, but no plant is truly deer-proof when food is scarce.

Clasping Arnica is a perennial wildflower native to Alaska, Canada, and the lower 48 states. It grows to 2.5 ft and blooms Jul in full sun, with brown fruit.

More about this plant

Arnica lanceolata is a North American species of flowering plant in the family Asteraceae, known by the common name clasping arnica or lanceleaf arnica. It has a disjunct (discontinuous) distribution in western North America and northeastern 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
Full sun
Soil & moisture
High moisture
Soil pH
6–7.3
Fertility need
Medium
Adapts to
Coarse (sandy), Medium (loam)
Hardiness
USDA zone 5+
Size & form
Sources · Size & form
USDA PLANTS (DwCA, Zenodo 17903503) — Height, Mature — Height
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
2.5 ft
Spacing
2–2.5 ft apart from USDA planting density
Spread
Slow
Growth rate
Moderate
Growth form
Rhizomatous
Lifespan
Perennial · short-lived
Foliage
Broadleaf · medium texture
Active growth
Spring & summer
Fruit
Brown
Flower colour
Yellow 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, Sprigs
Seed starting
No stratification needed
Seeds ripen
Summer seed-collection / harvest window
In the trade
No known commercial source
Deer browsing
Low often deer-resistant
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 Documented caterpillar host
Named species (a documented Nearctic sample, not exhaustive) from NHM HOSTS (CC0).
How we know this (1) Methods & honest limits
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 (26) 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 — GloBI
[22] Conservation rank — NatureServe Explorer (CC BY)
[24] Functional traits — TRY Plant Trait Database (CC BY 4.0)
[26] Caterpillar species — NHM HOSTS (CC0)
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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