Twin Arnica

Arnica sororia

Pollinator plant

Growing it

When	Flowers May to July
Type	wildflower
Sun	Full sun
Water	Low
Soil	pH 5.5–7.5
Hardiness	zone 2–6
Mature height	0.4 m
Mature spread	0.45 m
Spacing	0.3 m
Years to maturity	3
Bloom	May–Jul
Flower colour	Yellow not verified, a genus-level estimate
In bloom	May June July
Native to	AB, SK

egg-shaped leaves about 10 cm long in opposite pairs

Where it has been recorded

BothSpecimensObservations

34 squares of about 28 km, each holding at least one record. A square is not a claim that the plant grows throughout it, and an unshaded square is unrecorded rather than empty. Darker squares hold more records, which follows roads and towns as much as it follows the plant. 40 herbarium specimens and 4 field observations this project may redraw. A filled dot is a pressed sheet somebody can re-examine; a hollow ring is a photograph identified by community agreement. Where the dots are dense is where people have looked, not where the plant is commonest, and empty ground is unsurveyed rather than unoccupied. How this map is made.

Which ecoregions the records fall in

Mixed Grassland south AB / SK: 14 records, medium confidence
Northern Continental Divide south AB: 14 records, medium confidence
Moist Mixed Grassland south AB / SK: 10 records, medium confidence
Fescue Grassland south AB: 7 records, low confidence
Aspen Parkland central AB / SK: 4 records, low confidence

These are counts of records collected somewhere in the region, which is the resolution of the evidence: the map above shows where inside it. A region with 3 records is not the same claim as one with three hundred, so the count travels with the region. A region missing from this list means nobody has recorded it there, which is not the same as the plant being absent. Records within 900 m of a border count for neither side, because the border is not drawn finely enough to say which one they are on. Source: GBIF occurrence search + PRESERVED_SPECIMEN pass, retrieved 2026-08-24. Boundaries digitised from the National Ecological Framework for Canada v2.2 (Ecological Stratification Working Group 1995), simplified to about 900 m for display: an outline is accurate to roughly a kilometre, not to the metre. How these counts are made.

See every observation, live and current, on GBIF or iNaturalist.

Documented animals

7 documented relationships.

nectar for

Andrena pallidifovea Specimen records from ecdysis.org
Brown-tailed Bumble Bee Specimen records from www.bumblebeewatch.org
Central Bumble Bee Specimen records from www.bumblebeewatch.org
Halictus ligatus Specimen records from ecdysis.org
Red-belted Bumble Bee Specimen records from www.bumblebeewatch.org
Yellow Cuckoo Bumble Bee Specimen records from www.bumblebeewatch.org
Yellow-fronted Bumble Bee LaManna et al. 2020

Also worth knowing

Safety

Toxicity not assessed, absence of a warning is not a guarantee of safety

Buying it

About $8–$16 per plant (estimate), usually from a native-plant nursery. Estimate (herb default); AB retail as of 2026

Where these numbers came from

Flower detail: not verified, a genus-level estimate