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Brassicaceae family

Holboell's Rockcress Arabis holboellii

Native Specialist-bee host

Holboell's Rockcress is a biennial wildflower native to Alaska, Canada, and Greenland. It grows to 2 ft and blooms Apr in full sun – part shade, with brown fruit. A host for pollen-specialist native bees.

More about this plant

Boechera holboellii, or Holbøll's rockcress, is a species of plant in the family Brassicaceae. Its cytology has been much studied by the Danish botanist Tyge W. Böcher. Circumscription of this species has varied, with earlier works treating it as a widespread, polymorphic species with several varieties, while more recently it has been treated as a much more narrowly defined species from Greenland. 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 – part shade
Soil & moisture
Medium moisture
Soil pH
5.4–7.4
Fertility need
Medium
Adapts to
Coarse (sandy), Medium (loam)
Hardiness
USDA zone 4+
Size & form
Sources · Size & form
USDA PLANTS (DwCA, Zenodo 17903503) — Height, Mature — Height
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
Height
2 ft
Spread
None — clumping
Growth rate
Moderate
Growth form
Single crown
Lifespan
Biennial · short-lived
Foliage
Broadleaf · medium texture
Active growth
Spring & summer
Fruit
Brown
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
Seed
Seed starting
No stratification needed
Seeds ripen
Spring – Summer seed-collection / harvest window
In the trade
No known commercial source
Resprouts if cut
No
Herb layer — Sits in the herb of a layered food forest or polyculture.Open guide →
derived roles
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 ~7 caterpillar species

Arabis supports ~7 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 Arabis in North America, including:

Euchloe hyantis · California Marble ✦ Paramidea lanceolata · white / sulphur butterfly ✦ Pontia occidentalis · Western White ✦ Pontia sisymbrii · Spring White ✦ Anthocharis sara · Sara Orangetip Colias occidentalis · Western Sulphur
+ 8 more species →
Euchloe ausonides · Large Marble Euchloe creusa · Northern Marblewing Euchloe olympia · Olympia Marble Hellula rogatalis · Cabbage Webworm Moth Paramidea midea · white / sulphur butterfly Pieris napi · Green-Veined White Pieris virginiensis · West Virginia White Pontia beckerii · Becker's White
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

Specialist native bees depend on it.

Some native bees are pollen specialists (oligolectic) — they raise young only on pollen from particular plant genera. Arabis is a recorded specialist-bee host, so losing it can mean losing the bee that relies on it.

Xerces pollinator conservation →
Specialist hosts from Smith et al. 2024.
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 (1) 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).
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 (23) 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] Description — Wikipedia (CC BY-SA)
[19] Ecological value — Warren II 2026 (CC0) · Tallamy host-use counts · Smith et al. 2024 (CC BY)
[21] Photosynthetic pathway — TRY Plant Trait Database (CC BY 4.0)
[22] Caterpillar host count — Warren II 2026 (Dryad, CC0) · Tallamy host-use counts
[23] 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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