Smooth Aster vs Cow Parsnip - TreeTime.ca

Smooth Aster vs Cow Parsnip

Symphyotrichum laeve

Heracleum maximum

NOT AVAILABLE THIS SEASON - MIGHT RETURN

CUSTOM GROW

Smooth Aster
Cow Parsnip

Smooth Aster is a native perennial wildflower known for its violet-blue, daisy-like flowers. They bloom later in the season, from late summer to early fall. The flowers attract a variety of pollinators, including bees, butterflies, and other beneficial insects. It also serves as a host plant for the Silvery Checkerspot (Chlosyne nycteis) and Pearl Crescent (Phyciodes tharos) butterflies, further enhancing its ecological value. This easy-to-grow wildflower is well suited for native wildflower gardens, pollinator gardens, and naturalization projects.

The Smooth Aster’s non-aggressive root system allows it to spread slowly, and it is more likely to reproduce by seed, which can be controlled through deadheading. As a perennial, it dies back to the crown each winter, it will regrow from the base in the spring. Avoid disturbing the crown during late winter to ensure healthy growth the following season.

Cow Parsnip is a native perennial plant that grows tall with very large leaves and broad clusters of white flowers. It grows quickly, providing quick cover in disturbed areas.
Its flowers are large and plentiful, providing nectar and pollen for bees, flies, and butterflies. Its seeds are eaten by birds and small mammals. The young shoots of the plant are edible, but care must be taken as the sap of this plant can cause skin irritation (see below).
Note: The sap of the Cow Parsnip can cause phytodermatitis when exposed to ultraviolet light (sunlight). This can cause rashes or even burns. Care should be taken if pruning or handling this plant.

Smooth Aster Quick Facts

Cow Parsnip Quick Facts

Zone: 3a
Zone: 2a
Height: 0.9 m (3 ft)
Height: 1.8 m (6 ft)
Spread: 0.6 m (2.0 ft)
Spread: 1.2 m (4 ft)
Light: partial shade, full sun
Light: partial shade, full sun
Moisture: dry, normal
Moisture: normal, wet
Growth rate: very fast
Growth rate: fast
Life span: short
Life span: short
Growth form: upright
Spreading: seeds - low
Suckering: none


Toxicity: sap causes skin irritation
Foliage: very large, palmate leaves
Flowers: purplish-blue; daisy-like
Flowers: large clusters of white flowers
Bloom time: late summer to early fall
Bloom time: spring to early summer
Hybrid: no
Hybrid: no
Catkins: no
Catkins: no


Native to: AB, BC, SK, MB, ON
Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, PE
Other Names: glaucous aster, smooth blue aster
Other Names: american cow parsnip, common cow parsnip