Lupin

Where it grows

Big-leaf lupin originated in western North America, from British Columbia to California, where it occupies moist meadows, riverbanks, and clearings. New Zealand’s South Island Mackenzie Basin has been famously colonised by escaped garden lupins, painting the upland river flats in pink and purple swathes through November and December.

How to recognise it

A clump of distinctive palmate leaves, each made of nine to seventeen radiating leaflets, sits at the base; from it rises one or more tall, densely flowered spikes thirty to a hundred and twenty centimetres long. The pea-shaped flowers are stacked in whorls around the stem, often with each whorl a slightly different colour.

Garden & cultural uses

George Russell, an English railway worker, spent twenty years selecting his eponymous Russell Hybrids in the 1930s, which became the standard form sold in garden centres. Like all legumes, lupin roots host nitrogen-fixing bacteria; sweet lupins are now cultivated as a high-protein human food and stock feed.

In ecology

Garden lupin’s escape into New Zealand riverbeds has displaced native gravel-bed plants and altered the habitat for endangered braided-river birds, a reminder that beauty does not guarantee good ecological behaviour.