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Allium (amplectens)

John W. Hunt
Project Manager/Ecologist
University of California - Chico
California State University, Chico
Chico, California 95929-0555
530-898-4363 (fax)

Family Scientific Name: Liliaceae
Family Common Name: Lily
Scientific Name: Allium amplectens
Common Name: Clasping onion
Ecotype: Seed collected from The Nature Conservancy's Dye Creek and Vina Plains Preserves in Tehama County, California
General Distribution: California to British Columbia. Clay soils including serpentine, open or wooded places below 1,800 meters (Hickman 1993).
Propagation Goal: bulbs
Propagation Method: seed
ProductType: Container (plug)
Stock Type: Potted nursery stock
Time To Grow: 0
Target Specifications: First year bulb, typically ranging from 2-5mm in diameter (yes, very small).
Propagule Collection: Seed may be collected from dry flower heads and rubbed free from the bracts.
Propagule Processing: Seed may be collected from May through June (July). Seed can be retained on the heads well into summer, depending on the year. Approximately 450-650 seeds per gram, depending on individual, population, year and cleanliness of seed. Approximately 580 seeds per gram.
Pre-Planting Treatments: None, though clean dry seed was placed in dry, cold storage following collection and prior to sowing.
Growing Area Preparation/
Annual Practices for Perennial Crops:
Seed was directly sown into 1.5" deep flats containing a potting mixture of approximately 1:1:1:2 sand:pumice:peat moss:fir bark mixture. Flats were placed in an outdoor cold frame from late-fall though spring. Most seedlings were transplanted into various sized pots ranging form D-pots to 3x4" plastic containers (some seedlings were not transplanted) using the same potting mixture. The active growth phase can be somewhat extended by misting plants after the last spring rains, but care must be taken not to encourage rot. Dormancy can be induced by letting pots dry-down and then placing in dry storage until the following fall rains. Plants should be allowed to go dormant by early summer. Better growth may be obtainined during the first year by avoiding transplanting (seed directly into larger containers rather than flats). Based on results of direct seeding in the field, better above and below gound growth may be obtained by planting in native soil (e.g.loam) rather than potting soil. Loam appears to have lower fluctuations in moisture and temperature that stress seedlings and reduce growth during the first year. Growth from seed to dormant seedling follows the first fall rains through the spring-summer dry-down.
Establishment Phase: Initial germination was observed within 2 weeks; Germination rates for both populations were relatively low: 15% (Dye Creek) and 46% (Vina Plains) for seed cold, moist stratified in vermiculite at approximately 44F. For seed sown in outdoor coldframes germination rates of 14% (Dye Creek) and 37% (Vina Plains) were observed. Small bulbs (2-6mm in diameter) will be produced within 6-8 months.
Length of Establishment Phase: Transplantable sprouts were established within approximately 3-4 weeks.
Active Growth Phase: Active growth was observed following the onset of autumn rains (seed swelling) until drying down (die-back and dormancy) occurred inlate spring/early summer. The length of the active growth phase can be somewhat controlled with irrigation, but this species requires summer dormancy.
Length of Active Growth Phase: 6-8 months (late fall - early summer)
Hardening Phase: Hardening is not necessary as the active growth phase starts with the onset of fall rains and plants senesce around the end of spring or beginning of summer.
Harvesting, Storage and Shipping: Individuals go dormant following spring-summer dry down and die back. Dormant individuals were placed in dry storage at 60-70 degrees Farenheit.
Length of Storage: 3-5 months
Other Comments: Flowering: Late March - July (Oswald and Ahart 2002). Seed collection: May-June (July). Transplanted seedlings showed some sign of stress and seedlings transplanted earlier showed more vigorous growth subsequent to transplanting. Seed sown directly in the field showed above and below ground growth rates comparabel too, or better than seed grown under controlled conditions in well-drained potting soils. Heavier native soils may provide better growing conditions when kept moist compared to well-drained potting soils whose moisture and temperature may fluctuate more readily. Partial funding for this project was made available by the California State University Agricultural Research Initiative (ARI).
References: Hickman, James, Ed. 1993. The Jepson Manual: Higher Plants of California. University of California Press, Berkeley, California.; Oswald, Vern and Lowell Ahart. 2002. Selected Plants of Northern California and Adjacent Nevada. CNPS


Leigh, Mark; Matthew, Matthew R.; Pushnik, James C.; Boul, Rachelle D.; Hunt, John W.; Koenig, David A.. 2006. Propagation protocol for production of Container (plug) Allium amplectens bulbs Potted nursery stock; University of California - Chico Chico, California. In: Native Plant Network. URL: http://NativePlantNetwork.org (accessed 2020/10/23). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

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