Common Name: Riverbank Lupin

General Information

Lupinus rivularis is an annual to short-lived perennial plant, sometimes producing stems that are more or less woody and can persist. The plant produces a cluster of usually herbaceous, erect stems 30 - 150cm tall from a deep, tap-rooted rootstock[].
The plant is harvested from the wild for local use as a medicine. It is often grown as a soil stabilizer and improver, and is sometimes grown as an ornamental.

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 - British Colombia, Washington, Oregon, California

Habitat

Wet sandy or gravelly places on the coastal strand and in coastal scrub[].

Properties

Medicinal Rating
Other Uses Rating
Habit	Annual/Perennial
Height	1.00 m
Pollinators	Bees, Insects
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Lupinus rivularis is not a very cold-hardy plant, able to tolerate temperatures down to around -8°c when fully dormant, though probably hadier than this if the summers are hot. It is found at elevations up to 1,800 metres, growing in areas where the mean annual rainfall can range from 450 - 2,500mm[].
Requires a sunny position. Plants are found in the wild on well-drained, sandy or gravelly soils[]. In cultivation it generally grows well if given a sunny position in a deep, well-drained, moderately fertile soil with a neutral to slightly acid pH[].
A fast-growing plant, quickly developing a deep taproot[].
The plant is often annual to biennial in habit, and is more likely to live longer when growing on soils low in nitrogen, such as sand dunes, cut slopes along roadsides, or dredge spoils where competition is reduced[].
The plant’s showy floral display and pleasant scent make it appropriate for certain landscape uses along roadsides, around residential areas, and within parks where a larger, short-lived wildflower is desired[].
For seed production, the crop should be harvested just before fully mature to avoid excessive shatter. Green seeds thus harvested have dried without any apparent loss in viability[].
Closely related to Lupinus latifolius[].
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

None known

Medicinal

The plants are reported to have been used medicinally by the Thompson Indians of British Columbia[].

Agroforestry Uses:

An excellent pioneer species for low-fertility and dry sites, where it can create conditions suitable for the climax flora to become established[]. Given the plant’s rapid growth, it can be used to give a quick cover on critical erosion sites, including droughty, steep, low-fertility slopes. Because it also adds nitrogen to the soil (through N-fixing bacteria), it can facilitate the establishment of grasses and other wildflowers in restoration seedings[].
For soil enrichment through nitrogen fixation and addition of organic matter, riverbank lupine can be seeded as a winter cover and green manure crop, or used in reforestation projects. From laboratory assays, nitrogen fixation rates of its root nodules appear high, but actual levels of increase in field soil nitrogen have not been fully quantified[].

Other Uses

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 sow in mid spring in situ[, ]. You may need to protect the seed from mice. Germination should take place within 2 weeks.