Common Name: Big-Leaf Lupin

General Information

Lupinus polyphyllus is a stout, herbaceous perennial plant with usually unbranched stems. A very variable plant, some forms can grow up to 150cm tall with a large crown, whilst others can be highly rhizomatous, branching out for a metre or more but only growing 15 - 60cm tall[, ].
The plant is harvested from the wild for local use as a food and medicine. It is grown in plantations and in native woodlands in order to improve the soil, and is often grown as an ornamental in gardens.
Commonly grown as an ornamental, the plant has escaped from cultivation in some areas and become naturalized, often outcompeting native vegetation[].

Known Hazards

Lupinus species in general (and especially the seeds) contain a range of bitter-tasting alkaloids such as lupine, anagyrine, sparteine and hydroxylupanine. The pharmacological effects of these alkaloids are that they block ganglionic transmission, decrease cardiac contractility and contract uterine smooth muscle[]. When ingested in moderate to large quantities they can cause symptoms such as respiratory depression and slow heartbeat, sleepiness and convulsions[].
Alkaloid levels can vary greatly from species to species, and several members of the genus are used for food. In some species low-alkaloid, sweeter-tasting varieties have been developed. There are also techniques (particularly soaking and discarding the soak water) that lower the alkaloid levels.
Unless it is known that the plant is low in alkaloids then caution should be applied to any ingestion of the plant[].
Fungal toxins can readily invade the crushed seed and can cause chronic illness[].

Botanical References

,

Range

Western N. America - Alaska, British Columbia and Alberta, south to California and Nevada

Habitat

Usually found in wetland; at elevations from sea level to 3,000 metres[]. Commonly found in a variety of habitat types including seasonally dry to marshy meadows, wetlands and damp forests, along stream banks and ditches, and in disturbed areas[].

Properties

Weed Potential	Yes
Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.75 m
Pollinators	Bees, Insects
Cultivation Status	Wild

Cultivation Details

Lupinus polyphyllus is a very cold-hardy plant, able to tolerate temperatures down to around -35°c when fully dormant[].
An easily grown plant, succeeding in any moderately good soil in a sunny position[, ]. It strongly dislikes excessive winter wet[]. Requires an acid to neutral soil[]. Succeeds in poor soils[]. Members of this genus are mainly found in dry habitats, often on stony and low fertility soils[]. This species, however, is more common on moister, but well-drained, soils[].
Plants can be naturalized in the wild garden, especially on stream banks and for flowering above rough grass, where they may be short-lived but will self-seed[].
Plants dislike root disturbance.
There are some named varieties, selected for their ornamental value[].
The plants often do not flower in their first year from seed, but then generally flower freely[].
The flowers are pleasantly scented[].
Plants often become dormant in late summer, producing new shoots in early spring[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

Root - raw or cooked[]. The plant is considered edible by some Native American tribes, but thought to be poisonous by others[].

Medicinal

A decoction of the plant has been used as a tonic[].

The pounded seeds are mixed with water then strained. The resulting liquid is used to treat eye problems[]. (as Lupinus wyethii).

Agroforestry Uses:

The plant is grown as a soil improver in pine (Pinus species) and spruce (Picea species) plantations[]. They are deep rooted and suitable for erosion control and soil stabilization. Also, within their native range, they can be used in the revegetation of logging roads or clear cuts as nitrogen fixers[].
The flowers are very attractive to bees, being a rich source of nectar and pollen[].

Other Uses

The plants are used as bedding, and are strewn on the floor of sweat houses[]. (as Lupinus wyethii)

We have no specific information for this species, but the soakwater used to extract alkaloids from several edible species of lupin has been shown to be effective as a biocide[].

Propagation

Pre-soak the seed for 24 hours in warm water and then sow in early spring in a greenhouse[, ]. The seed is best sown in individual pots since the plants strongly resent root disturbance. Germination should take place within a couple of weeks. If sown in trays, then the seedlings should be potted up into individual pots as soon as they are large enough to handle. Plant out in early summer when the plants are around 15cm tall.
It should also be possible to sow the seed in situ in mid to late spring. Protect the seed from mice.
Basal cuttings, mid spring in a cold frame. Harvest the shoots when they are about 10cm long with plenty of underground stem. Pot them up in a very sandy soil in individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.
Division in early spring. Difficult.
Lupin propagation is usually carried out by seed - vegetative propagation is normally only used when propagating named cultivars[].