Plant of the Month: Eastern & Western Silver Asters
We've been a bit lax about updating our "Plant of the Month", so this month, we're doing two -- the Eastern (Symphyotrichum concolor) and the Western Silvery Aster (Sympohyotrichum sericeum).
Eastern Silvery Aster (Symphyotrichum concolor)
Identification:
Plant is elongate with flowers in a raceme rather than gathered together at the top of the plant. Floret rays are slightly blue to violet-blue. Leaves are smooth and untoothed. 1-2 foot height
Distribution:
New York and Massachusetts in the north, southward to Florida and Louisiana. G5, USA N5. Alabama (SNR), Delaware (SH, possibly extirpated), District of Columbia (SX, presumed extirpated), Florida (SNR), Georgia (SNR), Kentucky (S2), Louisisana (SNR), Maryland (S1), Massachusetts (S1), Mississippi (SNR), New Jersey (S2), New York (S1), North Carolina (S4), Rhode Island (SH), South Carolina (SNR), Tenessee (SNR), Virginia (S4).
Habitat:
Eastern Silvery Aster is found primarily near the east coast on sandy soils such as pine barrens.
Flowering Period:
September to October. The seeds are insect-pollinated and wind dispersed.
Western Silvery Aster (Sympohyotrichum sericeum)
Some botanists consider this to be one of the prettiest of the Aster Family. It has a distinctive swollen woody rootstock and sends up tall stalks (12-28 in / 30 - 70 cm) with leaves covered in fine hairs giving them a silvery sheen. Flowers are pink or pale purple and become increasingly redder with age. Seeds mature in 3-4 weeks and are wind distributed. Plants also reproduce by rhizomes. Beetle predation has been shown to drastically reduce seed viability.
Western Silvery Aster occurs in Manitoba, Ontario and 21 American states. Its range extends from Texas to Michigan and Manitoba. In Ontario it is found naturally in just two areas on the south shore of the Lake of the Woods and on an island in the lake.
Provincially rare (S2) in both Ontario and Manitoba and nationally threatened in Canada, it is still considered globally secure (G5) thanks to its widespread distribution in the United States.
Habitat:
It is found in sandy tall grass prairies, open bur oak savannahs, fields, dry open woods, and open rocky calcareous soils.
Wildlife:
Flowering when most crop plants are going to seed, the Western Silvery Aster provides an important source of nectar to pollinating insects. Asters may also play a role in increasing populations of crop pest predators such as Fall Armyworm (Spodoptera frugiperda) caterpillars and Corn Earworms (Helicopverpa zea) by providing nectar and pollen to bee and Tachinid flies whose larvae then feed on the crop pests.
Research from BC's Simon Fraser University suggests that leaving 30% of agricultural land uncultivated as habitat for wild pollinators may actually increase crop yields.
Western Silvery Aster is a larval host and/or nectar source for the Pearl Crescent (Phyciodes tharos) butterfly.
Flowering Period:
August to October.
Threats:
Western Silvery Aster populations are threatened by gravel extraction, the encroachment of woody species into prairie clearings invasion of non-native plants, pasture enhancement, off road vehicles, and urbanization.
