Early Yellowrocket Barbarea verna
Early Yellowrocket is an introduced biennial herb, found in Canada, the lower 48 states, and Saint-Pierre & Miquelon. It grows to 1.2 ft and blooms Mar – Jul.
More about this plant
Barbarea verna is a biennial herb in the family Brassicaceae. Common names include land cress, American cress, bank cress, black wood cress, Belle Isle cress, Bermuda cress, poor man's cabbage, early yellowrocket, early wintercress, scurvy cress, creasy greens, and upland cress. It is native to southern Europe and western Asia, and naturalized elsewhere It has been cultivated as a leaf vegetable in England since the 17th century. As it requires less water than watercress, it is easier to cultivate. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 6 derived from its U.S. range
- Height
- 1.2 ft
- Lifespan
- Biennial
- Foliage
- Evergreen broadleaf
- Flower colour
- Yellow AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~6 caterpillar species
Barbarea supports ~6 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 for introduced plants — native genera typically support far more.
Recorded feeding on Barbarea in North America, including:
+ 2 more species → ↑ show fewer
✦ Bees 49 bee visitors
49 native & managed bee species are documented visiting Early Yellowrocket — the 12 most-recorded:
Related plants
More Barbarea →
How we know this (3) Methods & honest limits
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.
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.
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.
Sources for this entry (23) Open & cited
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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