wild aster

Aster subulatus syn. Symphyotrichum subulatum
infestation in a creekbed (Photo: Sheldon  Navie)
old flower-heads with seeds (Photo: Sheldon  Navie)
close-up of flower-heads (Photo: Greg Jordan)
stems and upper leaves (Photo: Sheldon Navie)
flower-heads (Photo: Trevor James)
young plant with lower leaves (Photo: Sheldon Navie)
habit (Photo: Sheldon Navie)
infestation in a creek bed (Photo: Sheldon Navie)

Erect, many branched, almost hairless, spindly, dark green, summer growing annual or biennial herb, to1.8 m tall. The leaves are small and held close to the stem. The flowers are also small and produce wind blown seeds with fluffy parachutes.

Common names 
Also known as: annual saltmarsh aster, aster, aster weed, bushy starwort, eastern annual saltmarsh aster,, saltmarsh aster, sea aster, slender aster, slim aster, small saltmarsh aster,
Flowering time 
Flowers at any time of the year with the main flowering occurring between November and February.
Native to large parts of North America, Central America, the Caribbean, and South America
State declaration 
Council declaration 
Class R – Reduce populations
Known distribution 

This species is very widely naturalised in Australia. It is particularly common in eastern Australia (i.e. throughout Queensland, New South Wales, the ACT and Victoria) and relatively common in southern Australia (i.e. in Tasmania, in many parts of South Australia and in south-western Western Australia. Also naturalised in the southern parts of the Northern Territory and on offshore islands (i.e. Lord Howe Island, Norfolk Island and Christmas Island).`12


Prefers damp and poorly drained areas, but occurs in a wide range of habitats. Suited to all soil types 


Tall, spindly, straight-stemmed almost hairless annual or short-lived perennial herb up to 1.8 m tall, with small pale purple flowers produced on a many-branched flower stalk

Impact and control methods 

Wild aster (Aster subulatus) is regarded as an environmental weed in Victoria, South Australia, Western Australia, New South Wales and Queensland. It is a common and widespread weed of gardens, pastures, crops, roadsides, disturbed sites and waste areas. It is also invasive along waterways, in seasonally wet or poorly drained areas, and in permanently damp sites such as wetlands, swamp margins and drainage channels.

Stem and leaves 

Leaves linear-lanceolate to narrow-lanceolate, 1–15 cm long, 3–10 mm wide, apex acute, margins entire; stem-clasping.

Flowers and fruits 

The numerous flower-heads, 2-4 mm diameter, are in loose, leafy panicles with branched stems. The hairless, bracts surrounding the heads are often reddish with a green centre. Ray florets are white, pink or blue with 3–5 mm long ‘petals’. Central disc florets only number a few.

Achenes 1.5–2 mm long, narrow, 4–5 ribbed, sparsely hairy; pappus whitish. Weed of seasonally wet or poorly drained land and damp areas such as swamp edges and roadside drains.

Reproduction and dispersal 

By seed. ‘Seeds’ brown, about 2mm long with a conspicuous tuft of fine, pale hairs, 5-7mm long. Spread by: Windborne ‘seeds’.

Invades/threats: Coastal areas, particularly disturbed sites, gardens and lawns.