Raillardella (argentea)

Lee Riley Horticulturist USDA FS - Dorena Genetic Resource Center 34963 Shoreview Road Cottage Grove, Oregon 97424 541-915-7324 541-767-5709 (fax) lee.riley@usda.gov

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Family Scientific Name:	Asteraceae
Family Common Name:	Aster
Scientific Name:	Raillardella argentea
Common Name:	Silky Raillardella
Species Code:	RAAR
Ecotype:	Crater Lake
General Distribution:	California, Nevada, and Oregon
Propagation Goal:	Plants
Propagation Method:	Seed
ProductType:	Container (plug)
Stock Type:	107 ml (7 in3) container
Time To Grow:	17 weeks
Target Specifications:	Stock Type: Container seedling Root System: Firm plug in container.
Pre-Planting Treatments:	Seeds are sown directly into 107 ml (7 in3) cells (see growing medium below). Trays are sealed inside plastic bags and placed into cold stratification (1 to 3 °C) for 60 days. Trays are checked weekly and kept moist throughout the stratification period. If mold is evident, trays should be treated with 1% hydrogen peroxide.
Growing Area Preparation/ Annual Practices for Perennial Crops:	Greenhouse growing facility. Cells are lightly covered with nursery grit. Growing medium consists of 40:20:20:20 peat:composted fir bark:perlite:pumice with Nutricote controlled release fertilizer (18N:6P2O5:8K2O with minors; 180-d release rate at 21C) at the rate of 0.5 gram Nutricote per 107 ml container.
Establishment Phase:	Germination is uneven and slow. Complete germination may take up to 4 weeks. Following germination, plants are fertilized with soluble 12-2-14-6Ca-3Mg at 75 to 100 ppm for 2 weeks.
Length of Establishment Phase:	4 weeks
Active Growth Phase:	Raillardella argentea is very slow growing. The species is also very sensitive to over-watering. Careful attention to irrigation during the growing season is important. Fertilization depends on weather and physiological needs. Soluble 20-9-20 NPK, 20-18-18 NPK, or 17-5-24 NPK at 100 to 150 ppm is applied weekly throughout the growing season.
Length of Active Growth Phase:	13 weeks
Hardening Phase:	No dry-down is done to induce dormancy. Seedlings are moved to an outdoor growing area in mid-September.
Length of Hardening Phase:	4 weeks depending on chilling hours
Harvesting, Storage and Shipping:	Harvest Date: Mid October Storage Conditions: Seedlings are usually outplanted in fall. No storage except in outdoor growing area. Plants are well irrigated prior to shipping if shipped in containers.
Other Comments:	Perennial herb. Grows in dry, open, gravelly sites in conifer forests at high elevations. Likes semi-barren subalpine and alpine slopes and flats. Rare in Oregon, and only found at higher elevations. Grows from 4,900-12,800 feet.
References:	Dorena Genetic Resource Center Propagation Records, unpublished. Lady Bird Johnson Wildflower Center. Raillardella argentea (A. Gray) A. Gray. URL: https://www.wildflower.org/plants/result.php?id_plant=RAAR (Accessed 28 December 2023). Oregon Flora. Raillardella argentea (A. Gray) A. Gray. URL: https://oregonflora.org/taxa/index.php?taxon=7782 (Accessed 28 December 2023). USDA Natural Resources Conservation Service. Raillardella argentea (A. Gray) A. Gray. URL: https://plants.usda.gov/home/plantProfile?symbol=RAAR (Accessed 28 December 2023). Wildflowers of the Pacific Northwest. Turner Photographics. Raillardella argentea. URL: https://www.pnwflowers.com/flower/raillardella-argentea (Accessed 28 December 2023).

Citation:

Riley, Lee E.; Klein, Kassandra. 2024. Propagation protocol for production of Container (plug) Raillardella argentea Plants 107 ml (7 in3) container; USDA FS - Dorena Genetic Resource Center Cottage Grove, Oregon. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2025/04/20). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.