Iris (missouriensis)

Dave Skinner PMC Farm Manager USDA NRCS - Pullman Plant Materials Center Room 211A Hulbert Hall WSU Pullman, Washington 99164-6211 509-335-9689 509-335-2940 (fax) abbie@wsu.edu http://plant-materials.nrcs.usda.gov/wapmc

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Family Scientific Name:	Iridaceae
Family Common Name:	Iris
Scientific Name:	Iris missouriensis Nutt.
Common Name:	Western iris, Rocky Mountain iris
Species Code:	IRMI
Ecotype:	Paradise Creek drainage near Pullman, Washington.
General Distribution:	Western North America from British Columbia east to Minnesota and south to New Mexico. Usually found alongstreambanks and in open, moist to wet meadows. Uncommon west of the Cascade Mountains. Wetland indicator status is FACW+ (US Fish and Wildlife Service 1988).
Known Invasiveness:	Listed as a noxious weed in California (USDA NRCS 2004). <br> Roots are poisonous (St. John 1963) and were used by Native Americans as an ingredient in arrowhead poisons (Craighead et al 1963, Taylor 1992, Winegar 1982). <br>May outcompete grasses and be toxic to cattle (Whitson et al 1996).
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Time To Grow:	2 Years
Target Specifications:	Tight root plug in container.
Propagule Collection:	Fruit is a capsule. Seed is dark brown in color. Seed is collected when the capsules begin to split in early to mid August and should be cleaned and planted immediately. Seed can be shaken into envelopes or bags, or the entire capsule can be cut from the stem. 19,958 seeds/lb (USDA NRCS 2004) We determined 23,349 seeds/lb for this ecotype.
Propagule Processing:	Seed shaken from capsules needs no cleaning. Capsules can be crushed to release seed. Seed is cleaned with an air column separator. The seeds are large and dense and are easily cleaned.
Pre-Planting Treatments:	Germination is highest with fresh seed planted immediately after harvest. Extended cold, moist stratification is needed. In trials at the PMC with dry stored seed, no germination occurred without stratification and no seed germinated after 30 days cold, moist stratification. Seed left outside to germinate began emerging in late March. Germination after cool, dry storage and after warm, dry storage was equally low. Fresh seed sown covered in August and left outdoors germinated at 60% the following spring. A few seedlings emerged late in the same fall. Some germination will also occur after the second winter. Surface sown seed germination was uniformly low across all treatments, indicating light is not a factor in germination. Cool spring temperatures may also be necessary. Seedlings germinated outdoors and moved to the greenhouse did not survive. There may be large dissimilarities in germinability of seed collected from the same site in different years, probably due to variation in climatic conditions.
Growing Area Preparation/ Annual Practices for Perennial Crops:	In mid-August fresh seed is sown in 10 cu. in. Ray Leach Super cell conetainers filled with Sunshine #4 and covered lightly. A thin layer of pea gravel is applied to prevent seeds from floating. Conetainers are watered deeply and placed outside in the lath house. They remain there throughout the fall and winter.
Establishment Phase:	Containers remain outside. They are watered enough to keep the planting medium moist. Germination will begin as daytime temperatures warm in March, and may occur over 2-4 weeks.
Length of Establishment Phase:	7-8 months
Active Growth Phase:	Plants are watered as needed while outside and fertilized once a week with a water soluble, complete fertilizer. Growth is slow and plants will usually only produce 2-3 leaves during the first growing season. They must be overwintered and allowed to grow a second year in the containers in order to develop a tight root plug.
Length of Active Growth Phase:	2 years
Hardening Phase:	Fertilizer is withheld in September and water decreased to harden the plants for winter. Since the plants are grown outside, cold hardening is not needed.
Harvesting, Storage and Shipping:	Plants are stored in the lath house over winter with no protection except snow cover. Plants exposed to extreme low temperatures with no snow cover should be afforded some insulation. Regrowth will begin in early March as soon as temperatures begin to warm.
Other Comments:	Seed predation by insect larva has been observed. Plants may be propagated by division of the thick rhizome (Kruckeberg 1996). This method should only be used for plants growing in cultivation. Plants should not be dug up from stands in the wild.
References:	Craighead, John J., Frank C. Craighead, and Ray J. Davis. 1963. A Field Guide to Rocky Mountain Wildflowers. Houghton Mifflin Co. Boston, MA. 277 pp. Hitchcock, C. Leo, and Arthur Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Seattle, WA. 730 pp. Kruckeberg, Arthur R. 1996. Gardening with Native Plants of the Pacific Northwest. 2nd ed. University of Washington Press. Seattle, WA. 282 pp. Larrison, Earl J., Grace W. Patrick, William H. Baker, and James A. Yaich. 1974. Washington Wildflowers. The Seattle Audubon Society. Seattle, WA. 376 pp. Lyons, C.P. 1956. Trees, Shrubs and Flowers to Know in Washington. J.M. Dent & Sons (Canada) Limited. Vancouver, BC. 211 pp. Lyons, C.P. 1997. Wildflowers of Washington. Lone Pine Publishing, Renton, WA. 192 pp. Piper, C.V., and R.K. Beattie. 1914. The Flora of Southeastern Washington and Adjacent Idaho. Lancaster, PA. Pressof the New Era Printing Company. 296 p. Rickett, Harold W. 1973. Wildflowers of the United States: The Central Mountains and Plains. Vol. 6. (3 parts). McGraw Hill, New York. St. John, Harold. 1963. Flora of Southeastern Washington and of Adjacent Idaho. 3rd edition. Outdoor Pictures. Escondido, CA. 583 pp. Taylor, Ronald J. 1992. Sagebrush Country. Mountain Press Publishing Co. Missoula, MT. 211 pp. USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN) Online Database. National Germplasm Resources Laboratory, Beltsville, Maryland. URL: http://www.ars-grin.gov2/cgi-bin/npgs/html/taxgenform.pl (12 April 2005) USDA, NRCS. 2004. The PLANTS Database, Version 3.5 (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA. US Fish and Wildlife Service. 1988. National list of vascular plant species that occur in wetlands. US Fish & Wildlife Service Biological Report 88 (24). Whitson, Tom D., Larry C. Burrill, Steven A Dewey, David W. Cudney, B.E. Nelson, Richard D. Lee, and Robert Parker. 1996. Weeds of the West. 5th ed. Western Society of Weed Science. Newark, CA. 630 pp. Winegar, David. 1982. Desert Wildflowers: Drylands of North America. Beautiful America Publ. Co. Beaverton, OR. 144 pp.

Citation:

Skinner, David M,. 2005. Propagation protocol for production of Container (plug) Iris missouriensis Nutt. plants USDA NRCS - Pullman Plant Materials Center Pullman, Washington. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/07/02). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.