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Gentianaceae family

Rainier Pleated Gentian Gentiana calycosa

Native
Also known as: Bog Gentian · Explorer's Gentian

Rainier Pleated Gentian is a perennial wildflower native to Canada and the lower 48 states. It grows to 0.6 ft and blooms Apr in full sun, with black fruit.

More about this plant

Gentiana calycosa is a species of flowering plant in the family Gentianaceae. It is a herbaceous perennial gentian known by the common names explorer's gentian, Rainier pleated gentian, and mountain bog gentian. 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
5.6–7.5
Fertility need
Medium
Adapts to
Medium (loam), Fine (clay)
Hardiness
USDA zone 8+
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) — 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
0.6 ft
Mature width
~ 1 ft wide DERIVED derived estimate — open-grown crown allometry (height × growth-form ratio); not a measurement
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
Blue 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
Seed starting
No stratification needed
Seeds ripen
Summer – Autumn seed-collection / harvest window
In the trade
Routinely available
Deer browsing
Medium moderately palatable
Resprouts if cut
No
Ground-cover layer — Sits in the ground-cover of a layered food forest or polyculture.Open guide →
Rain garden / bioswale — Rated FACW on the wetland list — tolerates wet feet, so it suits the soggy zone of a rain garden or bioswale that catches and filters runoff.Open guide →
Living mulch / groundcover — Low, ground-hugging grower — can carpet bare soil as a living mulch, shading out weeds and holding moisture.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 · Apr — 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 ~1 caterpillar species

Gentiana supports ~1 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 modest genus.

Recorded feeding on Gentiana in North America, including:

Colias behrii · Sierra Sulphur Endothenia hebesana · Verbena Bud Moth Oncocnemis kelloggii · owlet moth Syngrapha hochenwarthi · owlet 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 10 bee visitors
Visitor records (observations, not exhaustive) from Noori et al. 2026 (CC BY 4.0) · GloBI →
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.
Frequently grows with

Across 34 U.S. vegetation-survey plots that recorded Rainier Pleated Gentian, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.

Subalpine Fir · 35% Sierra Shootingstar · 35% Lodgepole Pine · 35% Alpine Leafybract Aster · 35% Black Alpine Sedge · 32% Engelmann Spruce · 32% White Marsh Marigold · 29% American Alpine Speedwell · 29%
"%" = share of this plant's plots that also held the species. From sPlotOpen → (Sabatini et al. 2021, CC BY 4.0) — open vegetation plots: wild community composition, not garden design.
How we know this (3) Methods & honest limits
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 (33) 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)
[17] Invasive / introduced status — USDA PLANTS (DwCA, Zenodo 17903503) — native status
[18] Wetland indicator — USACE National Wetland Plant List (2022)
[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] Climate niche — Derived — realized climate niche from U.S. county occurrences (GBIF) × NOAA NCEI county climate normals 1991–2020 (public domain)
[27] Other common names — Wikidata (CC0)
[29] Flower-visitor value (derived) — Noori et al. 2026 (CC BY 4.0) · GloBI
[30] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[31] Caterpillar species — NHM HOSTS (CC0)
[32] 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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