Smooth Aster vs Sweetgrass - TreeTime.ca

Smooth Aster vs Sweetgrass

Anthoxanthum hirtum/Anthoxanthum nitens (Hierochloe odorata))

Symphyotrichum laeve

CUSTOM GROW

NOT AVAILABLE THIS SEASON - MIGHT RETURN

Sweetgrass
Smooth Aster

Sweetgrass is a cool-season perennial grass best known for its sweet, vanilla-like fragrance. The scent comes from coumarin in the leaves, which is pleasant to humans but has a bitter taste that makes the plant less appealing to deer and other herbivores. As a cool-season grass, Sweetgrass grows most vigorously in spring and fall, slowing or even going dormant during the heat of summer.

It spreads quickly through creeping rhizomes and can be difficult to remove once established, so it is best planted in areas where its spread will not cause problems. Due to its deep, vigorous root system and preference for moist soils, Sweetgrass is especially useful for erosion control, soil stabilization, riparian plantings, and naturalization projects.

Note: Sweetgrass was formerly classified under the scientific name Hierochloe odorata and its subspecies. The subspecies found in Canada are currently considered two distinct species: Anthoxanthum hirtum, which is native across Canada, and Anthoxanthum nitens, which is native to Eastern Canada. Because these two species are alike and share many overlapping common names, they are often considered as only one species.

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.

Sweetgrass Quick Facts

Smooth Aster Quick Facts

Zone: 1a
Zone: 3a
Height: 0.5 m (1.5 ft)
Height: 0.9 m (3 ft)
Spread: 0.5 m (1.5 ft)
Spread: 0.6 m (2.0 ft)
Light: partial shade, full sun
Light: partial shade, full sun
Moisture: normal, wet
Moisture: dry, normal
Growth rate: fast
Growth rate: very fast
Life span: short
Life span: short
Growth form: arching to upright, colony-forming
Spreading: rhizomes - high, seeds - low
Suckering: none

Toxicity: toxic if large amounts ingested

Foliage: fragrant, bright green
Flowers: purplish-blue; daisy-like
Bloom time: late summer to early fall
Hybrid: no
Hybrid: no
Catkins: no
Catkins: no


Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, NU, PE
Native to: AB, BC, SK, MB, ON
Other Names: bison grass, buffalo grass, holy grass, sweet grass, vanilla sweetgrass
Other Names: glaucous aster, smooth blue aster