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Hierochloe (odorata)

Tara Luna
USDI NPS - Glacier National Park
West Glacier, Montana 59936
(406) 888-7835

Family Scientific Name: Poaceae
Family Common Name: Grass Family
Scientific Name: Hierochloe odorata (L.) Beauv.
Common Synonym: Torresia odorata (L.) A.S. Hitchc.
Common Name: Sweet grass
Species Code: HIEODO
Ecotype: Moist meadows, Sweet Grass Hills, Liberty Co., MT.
General Distribution: Sweetgrass is a fragrant, rhizomatous perennial with culms that are usually red to purple at the base. Two types of leaf blade are present: 3-cm-long fertile stems that emerge early in the growing season, and 30- to 60-cm-long sterile stems that appear later in the summer. Sweetgrass seldom produces flowering stalks. The pyramidal shaped inflorescence appears in spring and early summer and consists of several shiny, bronze-colored spikelets. Each spikelet is surrounded by transparent, membranous glumes, which fall soon after maturation. Three flowers are borne in each spikelet but only one produces a seed. It is a circumboreal species that grows in moist prairie grasslands and montane to subalpine meadows, wetland margins, sloughs and streambanks. In North America, it is found from Alaska to Labrador, south to Oregon, Nevada, Arizona, and through the Rocky Mountains to New Mexico; also east to South Dakota, Indiana, and Pennsylvania.
Propagation Goal: plants
Propagation Method: vegetative
ProductType: Container (plug)
Stock Type: 800 ml containers
Time To Grow: 6 Weeks
Target Specifications: Stock Type: Container divisions<br> Height: 6 to 10 true leaves; 23 cm<br> Caliper: n/a<br> Root System: firm plug in container.
Propagule Collection: Rhizome divisions were separated from established nursery plants.
Pre-Planting Treatments: Rhizome divisions with at least 3 leaf bud shoots per rhizome are divided from nursery stock and planted into individual containers.
Growing Area Preparation/
Annual Practices for Perennial Crops:
Vegetative Propagation Method: Divisions.
Outdoor nursery growing facility.

Divisions are irrigated with Rainbird automatic irrigation system in early morning until containers are thoroughly leached. Average growing season of nursery is from late April after snowmelt until October 15th. First average frost is September 5th, although freezing temperatures can be expected anytime in Glacier National Park.
Establishment Phase: Rhizome sections are divided in June and transplantd into using 800ml (49 cubic inch) square containers using Promix #1 potting media (3:1 peat:perlite) with 4 grams of 13:13:13 N:P:K (Osmocote) controlled release fertilizer and 2 grams of micronutrient fertilizer per 800 ml container.
Length of Establishment Phase: 2 weeks
Active Growth Phase: Plants are irrigated frequently throughout the growing season and are root tight 6 weeks after initial division.
Length of Active Growth Phase: 5 weeks
Hardening Phase: Irrigation is gradually reduced in September and October. Plants are leached with clear water before winterization.
Length of Hardening Phase: 4 weeks
Harvesting, Storage and Shipping: Total Time to Harvest: 6 weeks from divisions.
Harvest Date: July
Storage Conditions: Overwinter in outdoor nursery under insulating foam cover and snow.
Length of Storage: 5 months
Other Comments: Seed propagation:
Seeds/Kg: 2,200,000/kgÿ
% Germination: 24%
% Purity: 100%
Seed Processing: Seeds are collected when florets turn to tan and papery. Fill rates are very low with this species.
Seed longevity is unknown.
Seed dormancy is classified as physiological dormancy.
Seed Treatments: cold moist stratification. Seeds are placed in moistened paper towels and placed inopened plastic bags under refrigeration at 3C.
A minimum of a 30 day stratification is recommended for adequate germination. Germination occurs at 21C.
Sowing/Planting Technique: Manual hand sowing; seeds are covered with medium.
Germination %: 23%
References: Flora of the Pacific Northwest, Hitchcock and Cronquist, 7th edition, University of Washington Press, 1973.
Seeding Rate Statistics for Native and Introduced Species, Hassell, Wendel, U.S.D.I. and U.S.D.A., April 1996.
Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination, Baskin and Baskin, Academic Press, 1998.
Seed Germination Theory and Practice, Deno, Norman, Penn State University, 1993.
Glacier National Park Native Plant Nursery Propagation Records, unpublished.


Luna, Tara; Evans, Jeff; Wick, Dale; Hosokawa, Joy. 2008. Propagation protocol for production of Container (plug) Hierochloe odorata (L.) Beauv. plants 800 ml containers; USDI NPS - Glacier National Park West Glacier, Montana. In: Native Plant Network. URL: http://NativePlantNetwork.org (accessed 2021/03/01). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

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