Symphyotrichum lanceolatum (Willow Aster) - photos and description

Symphyotrichum lanceolatum

Symphyotrichum lanceolatum

Symphyotrichum lanceolatum

Symphyotrichum lanceolatum

Symphyotrichum lanceolatum
Stems hairy in lines.

Symphyotrichum lanceolatum
Stems hairy in lines.

Symphyotrichum lanceolatum
Leaves usually entire

Symphyotrichum lanceolatum
Leaves sometimes have small teeth

General: Erect plants with branching growth habit, plants are rhizomatous. Stems hairy in lines.

Flowers: Flower heads numerous in leafy panicles, white in colour (field guides also list flower heads as pink to bluish-purple). I measured flower heads at 2 cm diameter.

Leaves: Leaves stalkless, linear to narrowly lanceolate, usually entire but sometimes toothed. We measured a leaf at 11 cm long and 1 cm wide.

Height: Height listed in Flora of Alberta to 120 cm. Plant in above photo was 135 cm tall.

Habitat: Stream banks, ditches, marshes, and moist spots.

Abundance: Common.

Origin: Native.

Synonym: This plant is listed in some of the field guides we use as Aster hesperius.

Similar species: This plant is similar to Symphyotrichum boreale. To identify Symphyotrichum boreale:
    - leaves uniform < 5 mm wide
    - inflorescence few headed, generally < 10 flower heads, inflorescence flat-topped
    - plants are few-branched.

To identify Symphyotrichum lanceolatum:
    - leaves > 5 mm in width
    - inflorescence many-headed, flower heads generally > 10 present
    - branching growth habit.

When and where photographed: Took the above photos August 20th, moist ditch, Duck Mountain Provincial Park, about 300 km northeast of our home in Regina, SK.