

Arrowleaf Balsamroot Balsamorhiza sagittata
Arrowleaf Balsamroot is a perennial wildflower native to Canada and the lower 48 states. It grows to 2 ft and blooms May in full sun – part shade, with brown fruit.
More about this plant
Balsamorhiza sagittata is a North American species of flowering plant in the tribe Heliantheae of the family Asteraceae known by the common name arrowleaf balsamroot. Also sometimes called Oregon sunflower or Okanagan Sunflower, it is widespread across western Canada and much of the western United States. Wikipedia →
Growing & care
USDA PLANTS · TRY- Sun
- Full sun – part shade
- Soil & moisture
- Medium moisture
- Soil pH
- 6.5–8
- Fertility need
- Low
- Adapts to
- Medium (loam), Fine (clay)
- Hardiness
- USDA zone 4+
- Height
- 2 ft
- Mature width
- ~ 2 ft wide DERIVED derived estimate — open-grown crown allometry (height × growth-form ratio); not a measurement
- Spacing
- 3–6 ft apart from USDA planting density
- Spread
- None — clumping
- Growth rate
- Moderate
- Growth form
- Multiple stems
- Lifespan
- Perennial · long-lived
- Foliage
- Deciduous broadleaf · medium texture
- Active growth
- Spring
- Fruit
- Brown
- Flower colour
- Yellow AI AI image-analysis of community-science photos (~87% expert agreement) — not a botanical record
- Propagate by
- Seed
- Seed starting
- Needs cold stratification a cold-moist spell before it germinates
- Seeds ripen
- Spring – Summer seed-collection / harvest window
- In the trade
- Routinely available
- Deer browsing
- High browsed readily
- Resprouts if cut
- No
Sow timing keys off your local last- and first-frost dates.
Wildlife & pollinators
How pollinator value is scored →❧ Caterpillar hosts Documented caterpillar host
Recorded feeding on Balsamorhiza in North America, including:
Wildlife & visitors 7 nectaring
Open records of who else uses Arrowleaf Balsamroot — a generalist food-web signal, kept separate from the keystone Ecological Value.
7 adult butterfly & moth species are recorded nectaring at its flowers — the most-recorded:
Across 226 U.S. vegetation-survey plots that recorded Arrowleaf Balsamroot, these catalog species turned up most often in the same plot — a real field co-occurrence signal, not a planting prescription.
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.
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.
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 (33) 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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