Prunus (subcordata)

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:	Rosaceae
Family Common Name:	Ros
Scientific Name:	Prunus subcordata
Common Name:	Klamath plum
Species Code:	PRSU2
Ecotype:	Klamath Basin, Oregon
General Distribution:	California, Oregon, and Washington.
Propagation Goal:	Plants
Propagation Method:	Seed
ProductType:	Container (plug)
Stock Type:	444 ml (27 in3) container
Time To Grow:	17 weeks
Target Specifications:	Stock Type: Container seedling Root System: Firm plug in container.
Pre-Planting Treatments:	Seeds are placed into fine mesh bags and soaked in a 1% hydrogen peroxide (3:1 water/3% hydrogen peroxide) 24 hours, rinsed, and placed in water for an additional 48 hours. Seeds are layered in peat and placed into cold stratification (1 to 3 °C) for 100 days. It is very important to check seeds in peat weekly. If mold is evident, seeds should be treated with 1% hydrogen peroxide.
Growing Area Preparation/ Annual Practices for Perennial Crops:	Greenhouse growing facility. Seeds are directly sown into containers. Seeds are lightly covered with nursery grit. Growing medium used is 40:20:20:20 peat:composted fir bark:perlite:pumice with Apex controlled release fertilizer (16N:5P2O5:10K2O with minors; 6 to 7 month release rate at 21C) at the rate of 2 gram Apex per 444 ml container.
Establishment Phase:	Germination is uniform, and is usually complete in 1 to 2 weeks. Plants are lightly fertilized with soluble 12-2-14-6Ca-3Mg at 75 ppm for 2 weeks following complete germination.
Length of Establishment Phase:	3 to 4 weeks
Active Growth Phase:	Once established, plants are fairly fast-growing. Soluble fertilizer (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 early September.
Length of Hardening Phase:	3 to 4 weeks depending on chilling hours
Harvesting, Storage and Shipping:	Harvest Date: Mid to late October Storage Conditions: Seedlings are usually outplanted in fall. No storage except in outdoor growing area. Plants are well irrigated prior to shipping and shipped in containers.
Other Comments:	Perennial tree. Found in California, Oregon, and Washington. It is the only wild plum in the PNW states and is easily identified when fruiting. Likes dry, rocky slopes in moist valleys. Low water use. Requires sun. Soil is best if moist and well drained. Hardy to USDA zone 7. Grows from sea level to 6,000 feet.
References:	Dorena Genetic Resource Center Propagation Records, unpublished. Lady Bird Johnson Wildflower Center. Prunus subcordata Benth. URL: https://www.wildflower.org/plants/result.php?id_plant=PRSU2 (Accessed 28 December 2023). Oregon State University College of Agricultural Sciences. Department of Horticulture. Landscape plants. Prunus subcordata. URL: https://landscapeplants.oregonstate.edu/plants/prunus-subcordata (Accessed 28 December 2023). USDA Natural Resources Conservation Services. Prunus subcordata Benth. URL: https://plants.usda.gov/home/plantProfile?symbol=PRSU2 (Accessed 28 December 2023).

Citation:

Riley, Lee E.; Klein, Kassandra. 2024. Propagation protocol for production of Container (plug) Prunus subcordata Plants 444 ml (27 in3) container; USDA FS - Dorena Genetic Resource Center Cottage Grove, Oregon. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2025/02/24). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.