Penstemon (attenuatus)

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:	Scrophulariaceae
Family Common Name:	Figwort
Scientific Name:	Penstemon attenuatus Dougl. ex Lindl.
Common Name:	Taper-leaf penstemon, sulfur penstemon
Species Code:	PEAT3
Ecotype:	Palouse region south of Moscow, ID
General Distribution:	Native to grasslands and open forests of eastern Washington, northeast Oregon, northern and central Idaho, and western Montana. The Palouse phase is var. attenuatus. Wetland indicator status is FACU (US Fish and Wildlife Service 1988).
Known Invasiveness:	not invasive
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Stock Type:	10 cu. in.
Time To Grow:	4 Months
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 late July and is stored in paper bags or envelopes at room temperature until cleaned. Plants hold their seed well after the capsules begin to split if winds are not excessive.
Propagule Processing:	Small amounts are rubbed to free the seed, then cleaned with an air column separator. Larger amounts are 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:	For this ecotype, 90 or more days of cold moist stratification is required. Unpublished data from trials conducted at the Pullman Plant Materials Center revealed that no emergence occurred without stratification. 45 days of cold, moist stratification resulted in 10% emergence. 90 days of cold, moist stratification resulted in 72% emergence. Containers sown in November and left outside under cool, fluctuating spring temperatures achieved 95% emergence. Seedlings which germinated in the greenhouse thrived in the constant warmth, so it is likely the longer stratification time and not the cool, fluctuating temperature was the factor in the increased germination. Surface sown seed in all treatments germinated at lower rates than covered seed. This, at least in part, may be due to desiccation from fluctuating moisture levels. Seed exposed to light might well germinate at higher levels under more favorable moisture conditions but the high germination and emergence from covered seed under extended cold, moist stratification indicates light is not a factor in germination of this ecotype. Seed of some penstemon species loses dormancy after 2« years (Allen et al 1990).
Growing Area Preparation/ Annual Practices for Perennial Crops:	In October or November seed is sown in 10 cu. in. Ray Leach Super cell conetainers filled with Sunshine #4 and covered lightly. A thin layer of coarse grit is applied to the top of the planting soil to prevent seeds from floating during watering. Conetainers are watered deeply and placed outside. Conetainers are moved to the greenhouse in January. Alternately, seed can be moist stratified in a refrigerator at 35-40 degrees F for 90+ days before sowing in the greenhouse.
Establishment Phase:	Medium is kept moist until germination occurs. Germination usually begins in 4 days and is complete in 7 days.
Length of Establishment Phase:	1 week
Active Growth Phase:	Plants are watered deeply every other day and fertilized once per week with a complete, water soluble fertilizer containing micro-nutrients. Plants may require water every day during the final part of the active growth period.
Length of Active Growth Phase:	3-4 months
Hardening Phase:	Plants are moved to the cold frame in late March or early April, depending on weather conditions. They are watered every other day if the weather is cool, and every day during hot, dry spells.
Length of Hardening Phase:	2-4 weeks
Other Comments:	No insect or disease problems have been noted. Both yellow flowered and purplish flowered plants are found on the Palouse. The yellow flowered phase is sometimes called sulfur penstemon.
References:	Allen, Phil S. and Susan E. Meyer. 1990. Temperature Requirements for Seed Germination of Three Penstemon Species. HortScience 25(2):191-193. Hitchcock, C. Leo, and Arthur Cronquist. 1973. Flora of the Pacific Northwest. University of Washington Press. Seattle, WA. 730 pp. Piper, C.V., and R.K. Beattie. 1914. The Flora of Southeastern Washington and Adjacent Idaho. Lancaster, PA. Press of 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. Strickler, Dee. 1997. Northwest Penstemons. The Flower Press. Columbia Falls, MT. 191 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/taxon.pl?448068 (1 March 2007). USDA NRCS. 2007. The PLANTS Database (http://plants.usda.gov, 1 March 2007). 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).

Citation:

Skinner, David M,. 2007. Propagation protocol for production of Container (plug) Penstemon attenuatus Dougl. ex Lindl. plants 10 cu. in.; 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.