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Rosaceae (Prunus)



Prunus (subcordata)


Rosaceae

Ros


Prunus

subcordata













Klamath plum

PRSU2

Klamath Basin, Oregon

California, Oregon, and Washington.


Plants

Seed

Container (plug)

444 ml (27 in3) container

17 weeks

Stock Type: Container seedling Root System: Firm plug in container.



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.

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.

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.

3 to 4 weeks

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.

13 weeks

No dry-down is done to induce dormancy. Seedlings are moved to an outdoor growing area in early September.

3 to 4 weeks depending on chilling hours

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.



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.

Dorena Genetic Resource Center Propagation Records, unpublished.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).

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 2025/06/25). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.