Astragalus (utahensis)

Scott Jensen Botanist USDA FS - Rocky Mountain Research Station, Shrub Sciences Laboratory 735 N 500 E Provo, Utah 84606 801-356-5128 801-375-6968 (fax) sljensen@fs.fed.us www.fs.fed.us/rm/boise

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Family Scientific Name:	Fabaceae
Family Common Name:	Legume Family
Scientific Name:	Astragalus utahensis (Torr.) Torr. & Gray
Common Name:	Utah locoweed, Utah milkvetch
Species Code:	ASUT
Ecotype:	27 sources collected from Utah and Nevada at elevations between 4060 ft. and 7400 ft.
General Distribution:	Stony hillsides, gravel-banks and bars, river and lake terraces, barren hilltops and openings in sagebrush, ascending from basin valley floors into pinyon-juniper and oak brush communities. Extending east from the southeast margin of the Snake River Plains in Idaho to the Bear River in Wyoming and in Utah to the western edge of the Uinta Basin and upper Price River, south up the Sevier valley to Wayne county, west to White Pine and Lincoln counties, Nevada.
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Stock Type:	7.5 cu.in. QPlug, (International Horticultural Technologies, LLC. Hollister CA. www.ihort.com)
Time To Grow:	16 Weeks
Target Specifications:	Transplantable plug
Propagule Collection:	Astragalus utahensis sets seed in pods which lie on the ground. This mandates hand collection from wildland stands. As the pods dry one end splits open releasing seed. Harvesting most populations from mid-June to mid-July results in little shattering loss. Later harvests are possible with increasing seed loss. Collected pods are placed in breathable bags until cleaned. Retained moisture in the pods is usually not high enough to cause seed spoilage if the pods are not dried following collection. However the best practice is to air dry the seed on a tarp until the pods are brittle then re-bag for storage until cleaning.
Propagule Processing:	Dry pods are run through a debearder. The cleanout door is left part way open allowing separated seed to drop free of the hammers. Pods are processed until shattered. Some small pods containing primarily immature seed will not break. Final cleaning is done on an air screen separator. Often the biggest contaminant is gravel. Care in collection will minimize this. Purity percentage can be in the upper 90's.Pods typically contain 30 ovules but ripen 8-9 seeds. The hard seeds store well at warehouse temperatures.
Pre-Planting Treatments:	Astragalus seed has both a hard seed coat and physiological dormancy. The seed coat must be scarified to allow water entry. Nicking with a razorblade, sanding, drum scarifying and acid treatments can be effective methods to reduce the seed coat. Each technique has its strengths and weaknesses. Our preferred method isa 20 minute soak in concentrated sulfuric acid followed by consecutive water rinses to remove all acid residue. On average this treatment was effective in reducing the seed coat to allow imbibition on 95% of the seed from 27 biotypes tested. Imbibition among individual biotypes ranged from 76% to 100%. Physiological dormancy is broken by moist cold stratification. In Petri dish studies of these 27 biotypes, germination rates reached 11%, 60%, 64% and 82% with no cold stratification, 2 weeks stratification, 4 weeks and 4 weeks with fungicide, respectively. The fungicide treatment involved wetting germination blotters with CaptanT Fungicide at labeled rates rather than distilled water. Ongoing work indicates leaching seed in water for 48 hours may yield high germination rates without cold treatments.
Growing Area Preparation/ Annual Practices for Perennial Crops:	Using conventional potting media and containers, Astragalus plants form thin root systems that fail to hold potting media together when transplanted. This can be remedied with a Q Plug. A Q plugs stabilized rooting media is a preformed sponge-like plug consisting of peatmoss and composted bark mulch held together with a tacifier. Regardless of root development the stabilized media holds together and is easily transplanted.
Establishment Phase:	Q Plugs should be heavily watered several times prior to planting to ensure complete saturation. Unsaturated plugs dry quickly at the surface slowing germination. Once saturated, plugs typically require less frequent watering than potting media. Greenhouse temperatures are set to 55ø F night, 65ø F day.
Length of Establishment Phase:	Germination occurs over several weeks.
Active Growth Phase:	Beginning at 4 weeks plants are fertilized with a 15:15:15: N, P, K liquid drench biweekly.
Length of Active Growth Phase:	12+ weeks
Other Comments:	Bruchidae weevils have damaged seed in 22% of our seed collections of this species. Applying 0.5 oz per plant of Imidaploprid at the pre to early flower stage failed to reduce infection rates.
References:	Cronquist, A., Holmgren, A. H., Holmgren, N. H., Reveal, J.L. and Holmgren, P. K. 1989. Intermountain Flora; Vascular Plants of the Intermountain West, U.S.A. Vol. 3, Fabales. New York Botanical Garden, Bronx, New York. Retrieved Dec, 13, 2006 from the Integrated Taxonomic Information System on-line database, http://www.itis.gov.

Citation:

Jensen, Scott L. 2007. Propagation protocol for production of Container (plug) Astragalus utahensis (Torr.) Torr. & Gray plants 7.5 cu.in. QPlug, (International Horticultural Technologies, LLC. Hollister CA. www.ihort.com); USDA FS - Rocky Mountain Research Station, Shrub Sciences Laboratory Provo, Utah. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/05/18). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.