Pomaderris hamiltonii
Common names
pale-flowered kumarahou
Biostatus
Native – Endemic taxon
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Threatened – Nationally Vulnerable | Qualifiers: Sp, DPS, DPT, RR
Category
Vascular
Structural class
Trees & Shrubs - Dicotyledons
Simplified description
Rare shrub to 4m tall with soft oval pointed leaves which have prominent veins on the underside and sprays of pale cream flowers. Leaves 5-6.5cm long by 2-3cm wide, tip pointed, with white star-shaped hairs underneath (lens needed). Fruit dry, small.
Flower colours
Cream
Detailed description
Shrub to small tree 3-6 m tall. branches upright rarely spreading, branches slender, bark dark brown, finely rugose. Seedling leaves dark green and glossey above, pale, and dull beneath, margins finely toothed. Leaves of seedlings, juveniles and adults petiolate, petioles pliant, dark green to brown green, somewhat rugose, at first finely covered in stellate hairs, trending to glabrous with age. Adult leaves 20 -80 x 10-40 mm, dark green above (not glossey), pale grey-green beneath, elliptic to elliptic-ovate; upper surface glabrous except for sparse, simple hairs present toward the sunken midrib; lower surface covered with fine, grey stellate indumentum, with larger simple and stellate veins on midrib and veins; margins entire, sometimes revolute; stipules 4-5 mm long, caducous. Inflorescence a terminal, open, many-branched corymb. Calyx reflexed, pale greenish; tube with scattered long, white, simple hairs until after anthesis. Petals cream; limb broad. Anthers oblong. Ovary with stellate hairs at apex, wholly immersed in calyx tibe at anthesis, ½ immersed at fruiting. Fruit cocci opening by percula, occupying ½ of their inner faces.
Similar taxa
Pomaderris kumeraho A.Cunn. is superficially similar. However, it is more usually a small shrub (1-2 m tall) with smaller, broadly oval, elliptic to elliptic-ovate, grey-green rather than dark green, much hairer leaves. It is also distinguished by its yellow rather than cream-coloured flowers. In P. hamiltonii the calyx tube is sparingly covered by long simple hairs and the petals are cream, while in P. kumeraho the calyx tube is densely covered by long simple hairs and the petals are yellow. The two species often grow sympatrically. Pomaderris kumeraho has 2n = 24 chromosomes and produces seed sexually, P. hamiltonii is triploid (2n = 36) and produces seed through apomixis.
Distribution
Endemic. North Island only, Pouto Peninsula, on road to Tinopai, vicinity of Warkworth and Omaha, near Kaiaua and Miranda, and on Great Barrier Island
Habitat
Coastal to lowland in open successional habitats and shrubland. Often found along roadside cuttings where the constant disturbance provides an ideal habitat.
Threats
Many populations occur on roadside cuttings where they are at constant risk from road maintenance crews, roadside spraying, and road widening. Some populations have been lost through natural succession
Detailed taxonomy
Genus
Family
Synonyms
None
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
(August-) October (-November)
Fruiting
(November-) December - January
Propagation technique
Easy from fresh seed, though can be slow to germinate. Semi-hardwood cuttings strike with difficulty. Recent experimentation has found that cuttings strike well if placed in untreated saw dust. Once established this species often naturalises in suitable gardens. It is an attractive small tree, which makes an excellent shelter belt or specimen tree. It is inclined to be short-lived and is prone to verticillium wilt.
Other information
Etymology
pomaderris: Lid skin
hamiltonii: Named by Lucy Moore after Dr MW Hamilton, director general of the DSIR from 1953 to 1971.
Chromosome number
2n = 36
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | At Risk – Naturally Uncommon | Qualifiers: RR, Sp
2012 | At Risk – Naturally Uncommon | Qualifiers: RR, Sp
2009 | At Risk – Naturally Uncommon | Qualifiers: RC
2004 | Sparse
Regional conservation statuses
Auckland: 2025 | Regionally Threatened – Regionally Vulnerable | Qualifiers: DPS, DPT, NStr, PF, RR, TL
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Auckland conservation status information is sourced from the “Conservation status of vascular plant species in Tāmaki Makaurau / Auckland” Simpkins E et al. (2025) report.
Referencing and citations
Attribution
Fact sheet prepared by P.J. de Lange for NZPCN (1 June 2013)
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Pomaderris hamiltonii Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/pomaderris-hamiltonii/ (Date website was queried)