Common Name: One-Leaved Onion

General Information

Allium unifolium is a herbaceous, perennial plant producing 2 - 3 leaves 18 - 50cm long and a flowering scape 20 - 80cm tall from an underground bulb[].
The plant is harvested from the wild for local use as a food.

Known Hazards

Although no individual reports regarding this species have been seen, there have been cases of poisoning caused by the consumption, in very large quantities and by some mammals, of certain members of this genus. Dogs seem to be particularly susceptible[].

Botanical References

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Range

South-western N. America - Oregon, California and Mexico (northern Baja California)

Habitat

Moist soils in pine or mixed evergreen forest in the coastal ranges of California[, ]. Moist, clay soils, including serpentine, usually along streams; at elevations up to 1,100 metres[].

Properties

Edibility Rating
Habit	Bulb
Height	0.60 m
Pollinators	Bees, Insects
Cultivation Status	Wild

Cultivation Details

Although capable of tolerating winter temperatures considerable below zero, Allium unifolium grows in areas with a distinct dry season in the summer and autumn, and the bulbs tend to rot when grown in cool wet climates, even if they are given sharp drainage[]. When growing it in moister environments, the plant needs some protection from the wet - this can sometimes be achieved by simply placing a cloche over the plant after flowering, or by growing it in a frame[, ].
Prefers a hot dry sunny position in a light, rich well-drained soil[, ]. This species is difficult to maintain under cultivation in Britain, our weather is probably too wet and cool for it to really thrive[]. The plant has a summer resting period when it should be kept dry and so it is best grown in a cold greenhouse or bulb frame[]. Placing a cloche over outdoor-grown plants in the summer, especially after flowering, will help to ripen the bulbs[]. Most members of this genus are intolerant of competition from other growing plants[].
This species is not fully hardy in Britain and is unlikely to survive in the colder parts of the country. It is only marginally hardy in N.W. England[].
A new bulb is formed annually, the old one withering away[].

Edible Uses

Bulb - raw or cooked[, , ]. The bulbs are 10 - 15mm in diameter[]. Together with the young shoots, they are fried and eaten[].

Leaves - raw or cooked[].

Flowers - raw. Used as a garnish on salads.

Medicinal

Although no specific mention of medicinal uses has been seen for this species, members of this genus are in general very healthy additions to the diet. They contain sulphur compounds (which give them their onion flavour) and when added to the diet on a regular basis they help reduce blood cholesterol levels, act as a tonic to the digestive system and also tonify the circulatory system[].

Agroforestry Uses:

Allium species usually grow well with most plants, especially roses, carrots, beet and chamomile, but they inhibit the growth of legumes[, , ]. They are, in general, bad companions for alfalfa - each species negatively affecting the other[].
Members of this genus are rarely if ever troubled by browsing deer[].

Other Uses

Although no specific mention has been seen for this species, the juice of most species in this genus (especially those with a strong onion or garlic smell) can be used as a moth repellent[].
The whole plant is said to repel insects and moles[].

Propagation

Seed - sow spring in a cold frame. Prick out the seedlings into individual pots when they are large enough to handle - if you want to produce clumps more quickly then put three plants in each pot. Grow them on in the greenhouse for at least their first winter and plant them out into their permanent positions in spring once they are growing vigorously and are large enough.
Division in spring. The plants divide successfully at any time in the growing season, pot up the divisions in a cold frame or greenhouse until they are growing well and then plant them out into their permanent positions.