Bushy starwort, sea aster
Aster subulatus Michx.
Vascular – Exotic
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
Tall, spindly, straight-stemmed almost hairless annual or short-lived perennial herb up to 2 m tall, with small pale purple flowers produced on a many-branched flower stalk
Common in the North Island, also established in northern South Island.
Wetland margins and coastal places, also in drier habitats including roadsides, wasteland and open grassland.
Tap-rooted annual or short-lived perennial herb, glabrous or rarely with a few hairs on upper stem; stems erect, terete, sparingly branched below, 20-200 -(300) cm tall, rarely stems resprouting and somewhat woody after flowering. Mid cauline lvs lanceolate to linear, apetiolate and cuneate, acute, crenulate or remotely serrulate, 35-150 × 3-10-(20) mm; lowermost lvs mostly petiolate, elliptic, cuneate, obtuse; uppermost lvs linear. Infl. a many-headed diffuse panicle. Capitula 2-5 mm diam. Involucral bracts very unequal; inner bracts narrow-oblong to subulate, acute to slightly acuminate, green toward apex and along midrib, purplish at apex and margins, 5-8 mm long; outer bracts not wholly herbaceous, c. 2 mm long. Ray florets numerous; ligules white to pale purple, c. 1-2 mm long. Achenes subcylindric to ellipsoid, compressed, 4-5-ribbed, 1.5-2.2 mm long, with sparse antrorse hairs.
No similar species.
Summer to winter
Wind dispersed seed.
North America, possibly also Central and South America
Reason for introduction
Unknown, seed or soil contaminant
Can be controlled manually, mechanically or herbicidally depending on situation.
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Webb et al. (1988).
References and further reading
Webb, C.J.; Sykes, W.R.; Garnock-Jones, P.J. (1988). Flora of New Zealand Volume 4: Naturalised pteridophytes, gymnosperms, dicotyledons. Botany Division, DSIR, Christchurch.
Popay et al (2010). An illustrated guide to common weeds of New Zealand, third edition. NZ Plant Protection Society Inc, 416pp.
Johnson PN, Brooke PA (1989). Wetland plants in New Zealand. DSIR Field Guide, DSIR Publishing, Wellington. 319pp.