Aster vialis

Common Names:
way-side aster
(Bradshaw) Blake
Growth Habit:
CPC Number:
Profile Contributors:
Edward Guerrant, Ph.D.
Partially Sponsored

Reference Links

ITIS - Tropicos - USDA Plants - Fish & WildLife

Participating Institutions

The following Participating Institutions are custodians for this species in the CPC National Collection:
Rae Selling Berry Seed Bank & Plant Conservation Programs
Cincinnati Zoo & Botanical Garden

The conservation of Aster vialis is partially sponsored.
Edward Guerrant, Ph.D. contributed to this Plant Profile.


Like so many other species, wayside aster is fighting an uphill battle to survive. To add insult to injury, it is not even a very attractive plant. Wayside aster lacks the showy, petal-like "ray flowers" that help many recognize other asters. This understated flower is threatened by habitat changes within its limited range in and around Oregon's Willamette Valley, and is in danger of quietly disappearing. Seedling recruitment appears nonexistent in some populations, a grave sign of its uncertain future.

Wayside aster's reproductive biology and habitat requirements make it especially vulnerable in human altered ecosystems. While many plant species self-pollinate, Aster vialis require pollen from other individuals in order to produce seeds. Increasing forest fragmentation makes obtaining pollen more difficult as great distances often separate plants. Even after this distance barrier is overcome, seed set is low. Experimental hand pollinations in the greenhouse typically produce few seeds. Additionally, germination rates are often extremely low in laboratory conditions. These low germination rates likely reflect that specific conditions, such as light and an absence of leaf litter, are necessary in order to break dormancy.

Vigorous and reproductive Aster vialis plants are found in habitats that receive abundant light. Fire historically played a large role in maintaining open understory habitats in and around the Willamette Valley. As opposed to the clear-cut or regeneration forest harvest methods used today, fire historically did not result in the death of all the trees in the stand. Larger fire tolerant trees such as Douglas fir and ponderosa pine often survived and provided some shade. Natural regeneration after a fire is patchy, resulting in forest gaps that provided habitat with high light levels suitable for wayside aster. Fire also burns away leaf litter, creating conditions thought necessary for germination by exposing the ground to sunlight and returning nutrients to the soil. In pre-settlement Oregon, wayside aster most likely did not persist in specific locations over long periods of time, but new populations were continually established as new habitats were created by natural disturbances. Under land-use practices today, this regeneration cycle is made more difficult due to a lack of available habitat.

Distribution & Occurrence


Conservation, Ecology & Research