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Allium (acuminatum)

Dave Skinner
PMC Farm Manager
USDA NRCS - Pullman Plant Materials Center
Room 211A Hulbert Hall WSU
Pullman, Washington 99164-6211
509-335-2940 (fax)

Family Scientific Name: Liliaceae
Family Common Name: Lily
Scientific Name: Allium acuminatum Hook.
Common Name: Hooker's or Tapertip onion
Species Code: ALAC4
General Distribution: Western US east to Montana and south to New Mexico where mean annual precipitation ranges from 10-60 inches. In eastern Washington it is commonly found in dry, often rocky areas of open grassland.
Propagation Goal: bulbs
Propagation Method: seed
ProductType: Container (plug)
Time To Grow: 3 Years
Target Specifications: Bulbs 4-5 mm in diameter
Propagule Collection: Seeds are collected when the capsules begin to split in July. Capsules can be collected individually or the entire stalk cut. Seed is black in color. Seed is stored in paper bags or envelopes at room temperature until cleaned.
We determined 253,691 seeds/lb for this ecotype.
Propagule Processing: Small amounts are rubbed to free the seed, then cleaned with an air column separator. Larger amounts could probably be threshed with a hammermill, then cleaned with air screen equipment. Clean seed is stored in controlled conditions at 40 degrees Fahrenheit and 40% relative humidity.
Pre-Planting Treatments: Cool, moist stratification and cool growing conditions are needed. No seed germinated without pretreatment. 30 days of cool, moist stratification resulted in a few seeds germinating, but they did not survive in the greenhouse. High germination was obtained from seeds sown in flats and left outside under cool, fluctuating spring temperatures. Seedlings which germinated outside died when placed in the greenhouse.
Growing Area Preparation/
Annual Practices for Perennial Crops:
In November, seed is sown in flats filled with Sunshine #4 and covered lightly. A thin layer of sand is applied to prevent seeds and planting soil from floating. Flats are watered well and placed outside.
Establishment Phase: Flats remain outside. They are watered only during dry spells. Germination will begin as daytime temperatures warm in March, and may occur over 2-4 weeks. Some additional seed will germinate the year following sowing.
Length of Establishment Phase: 2 months
Active Growth Phase: Plants are watered as needed while outside and fertilized once a week with a water soluble, complete fertilizer. They are moved to the lath house in June. Plants will begin to go dormant in July. Water is cut back and fertilizer is withheld as the plants dry down. Flats remain in the lath house for at least 3 growing seasons.
Length of Active Growth Phase: 3 years
Hardening Phase: Plants are dormant as winter approaches. They are stored in the lath house over winter. Flats should be covered with an insulating material to protect the bulbs from extreme cold if snow cover is lacking. Regrowth will begin in early March as soon as temperatures begin to warm.
Harvesting, Storage and Shipping: Bulbs are harvested in the fall of the third growing season by sifting the potting soil thru a sieve. Pea gravel should not be used to cover flats because it is roughly the same size as the bulbs and therefore difficult to separate. Bulbs range in size from 3-5 mm in diameter. They can be stored in dry conditions for a short period prior to planting. We have not attempted to store bulbs for a longer period.
Other Comments: No insect or disease problems have been noted.
Bulbs may need initial protection from rodents after outplanting.
References: Hitchcock, C. Leo, and Arthur Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Seattle, WA.
Kruckeberg, Arthur R. 1996. Gardening with Native Plants of the Pacific Northwest. 2nd ed. University of Washington Press. Seattle, WA.
St. John, Harold. 1963. Flora of Southeastern Washington and of Adjacent Idaho. 3rd edition. Outdoor Pictures. Escondido, CA.
USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
Young and Young. 1986. Collecting, Processing and Germinating Seeds of Wildland Plants. Timber Press. Portland, OR.


Skinner, David M,. 2004. Propagation protocol for production of Container (plug) Allium acuminatum Hook. bulbs USDA NRCS - Pullman Plant Materials Center Pullman, Washington. In: Native Plant Network. URL: http://NativePlantNetwork.org (accessed 2020/09/18). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

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