Kunzea robusta de Lange & Toelken

kānuka, rawirinui

New Zealand endemic.

Common in cultivation (previously in part under the name K. ericoides or K. ericoides var. ericoides).

Widespread in the North and South Islands of New Zealand, an important component of successional shrubland and forest.

• Mainly large trees with broad spreading canopies up to ± 30 m tall.
• Branchlets hairy, in some populations with hairs shedding to become hairless (but see K. ericoides).
• Leaves often with distinct juvenile and adult forms (but see K. amathicola).
• Leaf surfaces hairless except for margins and lower (abaxial) midrib, hairs on margin sometimes continuous but not usually meeting at leaf apex.
• Fruit uniformly hairy (but see K. sinclairii); usually 5, sometimes 6 locules.

Mainly trees with broad spreading canopies up to ± 30 m tall.

Bark stringy, or coarsely fragmented into small squares, firmly attached above, detaching basally, often hanging semi-detached; peeling as tabular strips up to 4 m long. Branchlets at first with copious hairs, then becoming hairless.

Leaves alternate, linear to lanceolate to oblanceolate, (3–)8–20(–28) mm long, 1–3 mm wide, or larger in coastal areas, light to dark green above, paler below, mature leaf surfaces mostly hairless with hairs confined to margins and abaxial (lower) midrib and usually not meeting at apex, surfaces not puckered; margins entire; tips acute; leaf stalks short or absent.

Early spring and summer flowers borne in compact clusters, late season inflorescences sometimes elongating up to 80 mm long; flowers ± 4–12 mm in diam., stalks present, petals 5, mostly white, oil glands mostly colourless (sometimes pink), drying opaque or grey; sepals 5, tips free, lobes persistent; stamens 15–58, white, longer than petals. Main flowering period: late spring to summer, but some flowers may be present in autumn or winter.

Fruit dry, 5(–6)-locular, ± 3–5 mm wide, uniformly hairy, flat-topped when valves closed.

Kunzea robusta is most like K. serotina and K. amathicola with which it often grows. From K. serotina it differs in growth habit (broad spreading canopies as opposed to pyramidal or columnar) and in that it possesses petals with oil glands colourless (rarely pink), drying opaque or grey, while in K. serotina the oil glands are yellow, drying pale yellow to ± colourless. In the latter too, the fruit is normally 3–4-locular while K. robusta generally has 5, sometimes 6 locules. The bark of K. serotina readily flakes and curls so resembling wood-shavings or the bark of kōtukutuku / tree fuchsia (Fuchsia excorticata). The bark of K. robusta flakes in long, leathery tabular strips, usually with minimal secondary flaking.

Kunzea amathicola differs from K. robusta by the strongly dimorphic juvenile and adult foliage types, with plants exhibiting juvenile foliage able to flower (K. robusta juveniles will not flower), and leaf shape – mostly obovate to ovate in K. amathicola, linear to lanceolate to oblanceolate in K. robusta. The leaf margins of K. amathicola are copiously hairy with the thick bank of hairs meeting at the leaf apex, those of K. robusta are sparsely hairy or if hairy without the hairs meeting at the leaf apex. The inflorescences of K. amathicola are not clustered, rather they are elongate; those of K. robusta start out in small clusters with late season inflorescences shortly elongate.

Kunzea robusta and K. ericoides are both trees with hairless leaves except on margins and lower midrib, but the former has leaves broader towards the tip and hairy fruit, whereas the latter has linear leaves and hairless fruit. The branches of K. ericoides are often pendulous whereas those of K. robusta are very rarely so.

Kunzea robusta is a recently described species endemic to New Zealand (de Lange 2014). It has a 2018 conservation status of Threatened – Nationally Vulnerable. As currently defined, it is the most widespread indigenous Kunzea in New Zealand and therefore highly variable.

The genus Kunzea also occurs in Australia, where it is represented by more than 50 species of which three (K. ambigua, K. baxteri, K. parvifolia) are cultivated occasionally in gardens in New Zealand; another nine species are recorded as having been included in research trials or as rare garden occurrences.

• Flora of New Zealand Online
• GBIF
• iNaturalist NZ
• NZPCN