Vascular – Native
Dicotyledonous Herbs other than Composites
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Non-resident Native – Coloniser | Qualifiers: SO
Previous conservation statuses
2009 | Non-resident Native – Coloniser | Qualifiers: SO
2004 | Non-resident Native – Vagrant
Indigenous. In New Zealand known only from the Waimea Estuary, Nelson where it was first discovered in 1993. Common in Australia where it is known from Western Australia, South Australia, Victoria, New South Wales and Tasmania.
A species of usually silty to muddy ground within estuaries, usually found growing just above the mean high tide mark in places which would be subjected to frequent salt-water immersion during storms or Spring/King tides.
Small procumbent subshrub forming dense patches up to 1 x 1 m. branches procumbent up to 150 mm tall, more or less glabrous. Leaves more or less succulent, sessile, 5-20 x 10-3 mm, glaucous to dark green, linear-lanceolate to linear-obovate, apex acute, base attenuate, glabrous. Flowers solitary; pedicels 0-1.5 mm long, calyx 5-7 mm long, tubular, teeth 5, triangular, 1/4 to 1/3 the length of tube, outer surface glabrous, inner pilose hairy; corolla 10 mm long, tubular white; 5-lobed, lobes 2-4 mm long, linear-ovate to linear-elliptic, acute; stamens 5, exserted, filaments attached 1-1.5 mm below throat; ovary 1-2-locular, style exserted, stigmas ovoid. Capsule c.3 mm long, obovoid, shorter than calyx, indehiscent (capsules rarely seen in New Zealand material). Seeds 1-2.
None. Though the grey-green, succulent leaves mean that sterile plants could be confused with Suaeda novae-zelandiae Allan which grows in similar habitats. From Suaeda, Wilsonia differs by its more upright growth habit and solitary, white, tubular non-bracteolate rather than the compact green or red-green, bracteolate flowers of Suaeda.
October - February
December - April (rarely produced in New Zealand)
Easily grown from stem cuttings. However, requires a water logged soil in full sun to flourish. In good conditions inclined to become invasive.
Not Threatened. Apparently a recent arrival ( at least there are no records of it prior to 1993) which has successfully colonised the Waimea Estuary. It shoudl probably no longer be regarded as a vagrant, despite the fact it rarely sets seed. For it spreads readily by asexual means.
wilsonia: Named after John Wilson, 18th century amateur botanist and author of A Synopsis of British Plants, published in 1744
Where To Buy
Not commercially available
Actively and aggressively spreading, this species may require management and control. It could be introduced. As far as is known all spread is vegetative, fruit being rarely (if ever) formed in New Zealand populations
Fact Sheet prepared for the NZPCN by P.J. de Lange 14 April 2006. Description by P.J. de Lange.
Please cite as: de Lange, P.J. (Year at time of access): Wilsonia backhousei Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/wilsonia-backhousei/ (Date website was queried)