Vascular – Exotic
Herbs - Dicotyledons other than Composites
Tall leafy herb dying overwinter and re-establishing from seed the following spring, up to 2.5 m tall, with thick succulent, often red-coloured angular or round stems, hollow stems, leaves in pairs or threes up to 20 cm long with a long pointed tip and finely toothed, leaves have distinctive unpleasant smell when crushed, flowers showy, purplish pink or occasionally white, up to 4 cm long in large flower heads of up to 10 long stalked flowers.
Local and scattered throughout including Stewart Island, common in parts of Westland and in the vicinity of several North Island urban centres.
Margins of water bodies, especially gullies, wet roadsides and forest margins.
Annual, glabrous herb; stems erect, single but branched above, to c. 2.5 m high, succulent, ribbed, swollen at nodes. Petioles to c. 8 cm long, pink above, narrowly winged, with scattered purplish elongated glands in distal 1/2. Lvs opposite or in whorls of c. 3. Lamina 10-20 × 3-8 cm, lanceolate to ovate, sharply serrate; veins impressed above, raised below; base cuneate or attenuate; apex acuminate. Fls in diffuse cymes in upper lf axils of branches, shining. Bracts and lateral sepals 5-10 mm long, ovate, pink, acuminate. Posterior sepal forming large backwards projecting hood 2.2-3 cm long (excluding spur), pink or rose with dark spots inside; spur 5-7 mm long, rather stout, green. Corolla 2-lipped, white or pale pink; uppermost petal 1.5-2 cm long, subreniform; apex truncate to slightly emarginate; lateral petals very asymmetric, c. 3.5 cm long when stretched out, sharply bent in middle with lower halves forming a circular orifice enclosing the elongated anther mass. Anthers yellow. Capsule 2-3 cm long, usually purplish on exposed side, constricted in upper 1/2, with 5 acute ridges. Seed 3.5-5 mm long, ± broadly ovoid, shining black, with a single ridge down 1 side; base truncate; apex slightly beaked.
Unlikely to be mistaken for any other plant.
November to March
Red/Pink, Violet/Purple, White
November to March
Seed dispersed by water and contaminated machinery, garden discards. Seed capsule 2-3 cm long, usually purplish on exposed side, constricted in upper 1/2 with 5 acute ridges. Seed 3.5-5 mm long, more or less broadly ovoid, shining black, with a single ridge down one side; base truncate; apex slightly beaked. (Webb et al 1988)
Reason for introduction
Rarely controlled, but can be controlled manually, mechanically or herbicidally depending on situation.
impatiens: From the Latin impatiens ‘impatient, hasty’, referring perhaps to the manner in which the pods of some species explode (Johnson and Smith, 1986).
Factsheets 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.
Clapham, A.R.; Tutin, T.G.; Warburg, E.F. (1962). Flora of the British Isles. Cambridge University Press, Second Edition. 1269pp.
Johnson, A. T. and Smith, H. A (1986). Plant Names Simplified: Their pronunciation, derivation and meaning. Landsman Bookshop Ltd: Buckenhill, UK.