Ontario Wildflowers website

Arrow-leaved Aster
Symphyotrichum urophyllum
(formerly Aster sagittifolius)

Arrow-leaved Aster (Symphyotrichum urophyllum) Other common names: White Arrowleaf Aster

Other scientific names: Aster sagittifolius, Aster hirtellus, Aster urophyllus

Family: Composite Family (Asteraceae)

Group: Asters

Distinctive features: Leaves are sort of arrow-shaped, without a deep cleft at base. Branches sweep upward, close to main stem.

Similar species:
  •   Heart-leaved Aster (Symphyotrichum cordifolium) - Leaves larger and more heart-shaped.

  •   Calico Aster (Symphyotrichum lateriflorum) - Same habitat, smaller plant, horizontal branches, smaller leaves.

  •   Large-leaved Aster (Eurybia macrophylla) - In the woods; flower head is flat-topped; leaves are much larger.

  •   Azure Aster (Symphyotrichum oolentangiense)

Flowers: Summer, Autumn;  White;  7 or more parts (petals);  1.5cm in diameter. Ray flowers: 8-15, usually white, sometimes pale pink or bluish. Disc flowers: 8-20, yellow becoming purple. Flower heads are a panicle shape. Many flowers are arrayed along upward sweeping branches.

Leaves: Alternate, Simple;  Sparse, arrow-shaped, but in the form of a spear point, not the form of -> or <-. Narrowly egg-shaped and shallowly toothed. Leaf stalks (petioles) winged. Lower leaves may be somewhat heart-shaped. Lower leaves are the largest.

Height: 40-100 cm (15-39 in)

Stem: Smooth to somewhat hairy. Side branches are upward sweeping.

Habitat: Fields and Open Areas, Meadows;  Forest edges or dry open areas of woods. Widely distributed in southern Ontario.

Grows in Sun/Shade: Sun

Lifespan: Perennial.  

Books: Newcomb's Wildflower Guide: 454    Peterson's Field Guide to Wildflowers: 354   

Native/Non-native: Native

Status: Very common.

Notes: This Aster grows on the edges of forests. It is most easily confused with Heart-leaved Aster (Symphyotrichum cordifolium), which often grows very near or in the same area. It can also be confused with Calico Aster (Symphyotrichum lateriflorum) by the novice.

Photographs: 155 photographs available, of which 18 are featured on this page. SCROLL DOWN FOR PHOTOGRAPHS.

Range Map is at the bottom of the page

Arrow-leaved Aster (Symphyotrichum urophyllum)

Typical Arrow-leaved Aster with upswept stems and white flowers.

Arrow-leaved Aster (Symphyotrichum urophyllum)

Note the branches that sweep up and remain close to the plant. This is in contrast to Calico Aster (Symphyotrichum lateriflorum), with which Arrow-leaved Aster is sometimes confused.

Arrow-leaved Aster (Symphyotrichum urophyllum)

Arrow-leaved Aster (Symphyotrichum urophyllum)

A closer look at the flowers. Note they are typical Aster flowers in that the discs start out yellow, gradually turning purple as they age.

Arrow-leaved Aster (Symphyotrichum urophyllum)

A closer view of flowers.

Arrow-leaved Aster (Symphyotrichum urophyllum)

Arrow-leaved Aster (Symphyotrichum urophyllum)

An entire plant.

Arrow-leaved Aster (Symphyotrichum urophyllum)

A plant with smaller upswept stems.

Arrow-leaved Asters like to grow at the edge of woods and fields.

Arrow-leaved Aster (Symphyotrichum urophyllum)

The leaves which give this plant its name.

Note that the "arrow" aspect is an arrow without a very deep cleft at the base of the arrowhead (in the world of botany that cleft is referred to as a "sinus").

The upper surface.

Arrow-leaved Aster (Symphyotrichum urophyllum)

Another leaf.

Arrow-leaved Aster (Symphyotrichum urophyllum)

The underside of the leaf.

Arrow-leaved Aster (Symphyotrichum urophyllum)

Basal leaves.

Arrow-leaved Aster (Symphyotrichum urophyllum)

A leaf attached to the plant.

Arrow-leaved Aster (Symphyotrichum urophyllum)

A worn leaf, in September.

Arrow-leaved Aster (Symphyotrichum urophyllum)

The lower leaves are usually dried up by the time this plant is flowering.

Arrow-leaved Aster (Symphyotrichum urophyllum)

The upper stem has many smaller, non-arrow-shaped leaves, sort of like Heart-leaved Aster (Symphyotrichum cordifolium).

Arrow-leaved Aster (Symphyotrichum urophyllum)


Arrow-leaved Aster (Symphyotrichum urophyllum)

Going to seed in early October.

Range map for Arrow-leaved Aster (Symphyotrichum urophyllum)

PLEASE NOTE: A coloured Province or State means this species occurs somewhere in that Province/State.
The entire Province/State is coloured, regardless of where in that Province/State it occurs.

(Range map provided courtesy of the USDA website and is displayed here in accordance with their Policies)