Downy Paintedcup Castilleja sessiliflora
Downy Paintedcup is a perennial shrub native to Canada and the lower 48 states. It grows to 1.3 ft and blooms Apr in part shade – shade, with brown fruit.
More about this plant
Castilleja sessiliflora is a species of flowering plant in the broomrape family known by the common names downy paintbrush and downy paintedcup. It is native to the Great Plains of North America from southern Canada, through the central United States, to northern Mexico. It occurs as far west as the eastern slopes of the Rocky Mountains. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Part shade – shade
- Soil & moisture
- Low moisture
- Soil pH
- 6–7.4
- Fertility need
- Low
- Adapts to
- Coarse (sandy), Medium (loam)
- Hardiness
- USDA zone 4+
- Height
- 1.3 ft
- Spread
- None — clumping
- Growth rate
- Moderate
- Growth form
- Single crown
- Lifespan
- Perennial · long-lived
- Foliage
- Broadleaf · coarse texture
- Active growth
- Spring & summer
- Fruit
- Brown
- Flower colour
- Pink AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
- Propagate by
- Seed
- Seed starting
- No stratification needed
- Seeds ripen
- Spring – Summer seed-collection / harvest window
- In the trade
- Routinely available
- Resprouts if cut
- No
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts ~5 caterpillar species
Castilleja supports ~5 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 Castilleja in North America, including:
+ 8 more species → ↑ show fewer
✦ Bees 3 bee visitors
3 native & managed bee species are documented visiting Downy Paintedcup :
Related plants
More Castilleja →
How we know this (2) Methods & honest limits
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 (32) 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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