

Tall Thimbleweed Anemone virginiana
Tall Thimbleweed is a perennial wildflower native to Canada and the lower 48 states. It blooms May – Jul.
More about this plant
Anemone virginiana is an upright growing herbaceous species of flowering plant in the buttercup family Ranunculaceae. It is a perennial that grows 30–80 centimetres (12–31 in) tall, flowering from May until July. The flowers are white or greenish-white. After flowering, the fruits are produced in dense rounded thimble-shaped spikes 15–35 millimetres (0.59–1.38 in) long and 12 millimetres (0.47 in) wide. When the fruits, called achenes, are ripe they have gray-white colored, densely woolly styles, that allow them to blow away in the wind. The leaf structure is whorled halfway up the stem and each individual leaf appears to be deeply cut. It is native from eastern North America, where it is found growing in dry or open woods. This plant can be found in 38 out of the 50 states in the United States and is located anywhere from Maine to Minnesota going west, and found as far south as Georgia and Louisiana. Wikipedia →
Growing & care
USDA PLANTS · TRY- Hardiness
- ≥ zone 4 derived from its U.S. range
- Lifespan
- Perennial
- Foliage
- Broadleaf
- Flower colour
- White AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~1 caterpillar species
Anemone 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 Anemone in North America, including:
✦ Bees 2 bee visitors
2 native & managed bee species are documented visiting Tall Thimbleweed :
How we know this (4) Methods & honest limits
We read each species’ measured specific leaf area (leaf area per unit dry weight) from the Global Spectrum dataset and band it: thin & fast (high SLA), medium, or thick & tough (low SLA). The global median is about 10 mm²/mg.
Honest limits: A species-mean from pooled measurements — individual plants vary with light and site. A broad strategy signal, not a precise per-plant figure.
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 (25) 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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