Marsh Aster

Symphyotrichum boreale

KeystoneLarval hostBird foodPollinator plant

Growing it

When	Flowers July to September
Type	wildflower
Sun	Full sun, partial shade
Water	Medium, high
Soil	pH 5.5–7
Hardiness	zone 2–5
Mature height	0.6 m
Mature spread	0.6 m
Spacing	0.4 m
Years to maturity	2
Bloom	Jul–Sep
Flower colour	Purple not verified, a genus-level estimate
In bloom	July August September
Native to	AB, SK

lance-shaped leaves about 8 cm long

Where it has been recorded

BothSpecimensObservations

70 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. 47 herbarium specimens and 55 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

Mid-Boreal Uplands central AB / SK: 32 records, high confidence
Western Alberta Upland central AB: 30 records, high confidence
Boreal Transition central AB / SK: 26 records, high confidence
Aspen Parkland central AB / SK: 13 records, medium confidence
Slave River Lowland north AB: 10 records, medium confidence
Eastern Continental Ranges central AB: 9 records, medium confidence
Peace Lowland north AB: 6 records, low confidence
Moist Mixed Grassland south 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

15 documented relationships.

pollen for

Agapostemon texanus Robertson 1929
Ammophila procera Robertson 1929
Brachysomida nigripennis Robertson 1929
Colletes simulans Robertson 1929
Epuraea truncatella Robertson 1929
Halictus ligatus Robertson 1929
Liris argentatus Robertson 1929
Megachile latimanus Robertson 1929
Myospila meditabunda Robertson 1929
Sarcophaga sinuata Robertson 1929
Snowberry Clearwing Robertson 1929
Syrphus torvus Robertson 1929

nectar for

Arctic Fritillary Specimen records from iNaturalist.org
Half-black Bumble Bee Specimen records from iNaturalist.org
Yellow-collared Scape Moth Specimen records from iNaturalist.org

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 stocked by garden centres. Estimate (herb default); AB retail as of 2026

Where these numbers came from

Flower detail: not verified, a genus-level estimate