Agonis flexuosa (Willd.) Sweet

agonis, Australian willow myrtle, peppermint myrtle, peppermint tree, peppermint willow myrtle, peppermint willow, river myrtle, Swan River peppermint, Western Australian myrtle, Western Australian peppermint, willow myrtle

Australia: indigenous to south-western coastal regions of Western Australia.

In New Zealand cultivated as a landscape tree of parks and gardens; occasionally naturalised from nearby planted specimens. Agonis flexuosa ‘Nana’ (dwarf peppermint tree) is also cultivated in New Zealand and can be grown as a hedge.

Scattered records from mainly urban areas in the North Island and northern South Island of New Zealand.

• Weeping branches, zig-zagged leafy stems.
• Leaves long, to 150 mm, narrow and pendulous.
• Crushed leaves smell of peppermint.
• Flowers and fruit clustered.

Tree, growing to 10(–15) m tall. Agonis flexuosa ‘Nana’ is a compact shrubby selection that grows 1.2–1.8 m tall.

Bark fibrous, brown; branchlets usually almost hairless, often zig-zagged, changing direction at each node.

Adult leaves alternate, narrowly elliptic or narrowly ovate to sickle-shaped, 18–135(–150) mm long, 3.5–12 mm wide, pendulous, same colour on upper and lower surface; leaf blade flat, sometimes slightly twisted, hairless and surfaces not puckered; margins entire; tips pointed; leaf stalks absent or to 5 mm long.

Flowers in clusters, individual flowers ± 8–12 mm in diam., shortly stalked; petals 5, white; sepals 5, tips free, hairy, persistent; stamens white, shorter than petals. Main flowering period: spring to early summer.

Fruit dry, individual fruits tightly clustered into round balls, each fruit 3–4-locular, 2.5–4 mm wide. Seeds are mostly released upon the death of a branch.

The weeping branches, zig-zag towards the tips, bearing long, narrow and pendulous leaves that smell of peppermint when crushed, together with clustered flowers and fruit are unique to this species in New Zealand.

Agonis flexuosa is susceptible to myrtle rust (caused by Austropuccinia psidii).

Two varieties are recognised: A. flexuosa var. flexuosa and A. flexuosa var. latifolia; along with several cultivars. Taller growing selections are attributable to A. flexuosa var. flexuosa, whereas A. flexuosa var. latifolia has a smaller, usually shrubby habit, smaller (less than 45 mm long), often twisted leaves, and fewer (15–20) stamens. Agonis flexuosa ‘Nana’ is likely a selection of A. flexuosa var. latifolia.

Agonis is a genus of four species endemic to Western Australia. Agonis flexuosa is the only one that can grow to tree size; the others generally grow as tall shrubs.

• CitSciHub
• Flora of New Zealand Online
• GBIF
• iNaturalist NZ
• NZPCN
• Plants of South Eastern New South Wales
• VicFlora: Flora of Victoria
• Weeds of Australia: Biosecurity Queensland