silky aster

(Symphyotrichum sericeum)

Conservation Status
silky aster
  IUCN Red List

not listed


N5? - Secure

SNR - Unranked


not listed


Silky aster is 8 to 24 tall, erect, perennial forb that rises on a cluster of 1 to 5 or more clustered stems from a short, woody, corm-like caudex or rhizome.

The stems are erect, thin, wiry, brittle, grayish-to reddish-brown, and much branched above the middle. They are hairless or nearly hairless near the base and are densely covered with appressed, silky hairs toward the tip.

Basal leaves are inversely lance-shaped, to 2 long, and to wide. They are stalked, wedge-shaped at the base, and taper to a point at the tip with straight sides along the tip. There is 1 main vein and a network of smaller veins. The upper and lower surfaces are moderately to densely covered with long, silky hairs giving them a whitish- or grayish-green appearance. The margins are untoothed and have a fringe of silky hairs.

Lower stem leaves are similar to basal leaves but stalkless. They do not clasp the stem at the base. They have a short, sharp, abrupt point at the tip. Basal and lower stem leaves are usually absent at flowering.

Middle and upper stem leaves similar to lower stem leaves but lance-shaped, to 13 16 long, 3 16 to 5 16 wide, and angled or rounded at the base.

The inflorescence is an open, branched array (panicle) at the end of the stems and branches. The panicle has 1 to 5 or more short-stalked flower heads per panicle branch.

The flower heads are ½ to ¾ in diameter. The bracts at the base of the flower head (involucre) is ¼ to long and bell-shaped. They are arranged in 3 to 6 overlapping series. The outer series is egg-shaped, sharply pointed, and horizontally spreading. The middle series are bent backward. The inner series is linear and strongly ascending.

There are 10 to 30, usually at least 15, rose-purple to deep purple ray florets and 15 to 35, usually at least 25, disk florets. The disk florets are pink at first, later turning purple.

The fruit is a hairless, purple or brown achene with a tuft (pappus) of pale off-white or tan hairs attached.




8 to 24


Flower Color


Rose-purple to deep purple ray florets, pink disk florets


Similar Species


This is the only aster with leaves whitish-green due to a dense covering of silky hairs.


Dry. Prairies. Full sun.




August to October


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 24, 28, 29, 30.









  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Asteranae  


Asterales (sunflowers, bellflowers, fanflowers, and allies)  


Asteraceae (sunflowers, daisies, asters, and allies)  
  Subfamily Asteroideae  
  Supertribe Asterodae  
  Tribe Astereae (asters and allies)  
  Subtribe Symphyotrichinae  
  Genus Symphyotrichum (American asters)  
  Subgenus Virgulus  
  Section Concolores  

This and other asters were formerly place in the genus Aster. That genus was problematic, in that it did not include just one common ancestor with all of its lineal descendants and no others – it was not monophyletic. In 1994, the genus Symphyotrichum was resurrected to include most North American asters formerly in the genus Aster.


Subordinate Taxa






Aster sericeus

Aster sericeus var. sericeus

Lasallea sericea

Virgulus sericeus


Common Names


silky aster

western silver aster

western silverleaf aster

western silvery aster










A short, thickened, woody, persistent enlargement of the stem, at or below ground level, used for water storage.



Describing a leaf that wholly or partly surrounds the stem but does not fuse at the base.



A short, solid, vertical, thickened, underground stem that serves as a storage organ.



A whorl of bracts beneath or surrounding a flower or flower cluster.



Long, straight, and narrow, with more or less parallel sides, like a blade of grass.



A pyramidal inflorescence with a main stem and branches. Flowers on the lower, longer branches mature earlier than those on the shorter, upper ones.



The modified calyx composed of awns, scales, bristles, or feather-like hairs in plants of the Aster family such as thistles and dandelions.



A horizontal, usually underground stem. It serves as a reproductive structure, producing roots below and shoots above at the nodes.

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Silky Aster

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