RNGR.net is sponsored by the USDA Forest Service and Southern Regional Extension Forestry and is a colloborative effort between these two agencies.

U.S. Department of Agriculture USDA Forest Service Southern Regional Extension Forestry Southern Regional Extension Forestry

Skip to content. | Skip to navigation

The Forest Service National Center for Reforestation, Nurseries, and Genetic Resources (RNGR) is a leading source of technical information for nurseries and land managers regarding production and planting of trees and other native plants for reforestation, restoration, and conservation.

 
NPN Protocol Details Image

Rubus (ursinus)

Lee Riley
Horticulturist
USDA FS - Dorena Genetic Resource Center
34963 Shoreview Road
Cottage Grove, Oregon 97424
541-915-7324
541-767-5709 (fax)
leriley@fs.fed.us
Family Scientific Name: Rosaceae
Family Common Name: Rose
Scientific Name: Rubus ursinus
Common Name: California blackberry
Species Code: RUUR
Ecotype: Rogue River-Siskiyou National Forest
General Distribution: R. ursinus most commonly occurs below 900 m (3000 ft) elevation, with about 36 to 60 cm (14 to 24 in) of annual precipitation in canyons, disturbed sites, and fields; from Oregon to Lower California. R. ursinus is found in the Western United States including: Washington, Oregon, California, Idaho, and Montana. The western part of Canada is also included in the distribution of R. ursinus.
Propagation Goal: Plants
Propagation Method: Seed
ProductType: Container (plug)
Stock Type: 444 ml (27 in3) container
Time To Grow: 18 weeks
Target Specifications: Stock Type: Container seedling Root System: Firm plug in container.
Propagule Collection: Collect the fruits when ripe. Generally fruits ripen from June through August, and can be collected by hand. Berries can be stored in a plastic bag at ~4 °C until extraction, within two weeks or so to prevent mold growth.
Propagule Processing: Macerate berries thoroughly while still in plastic bag. Add water to bag to mix, and pour mixture in beaker. Add sufficient water. Water to berry mixture should be 3:1. Add pectinase (approximately 1 table spoon per liter) to volume and stir. Leave mixture at room temperature for 24 hours. Most seed should sink to bottom if filled and properly macerated initially. Pour off top layer of while gently mixing, or adding water from a faucet. Do not mix so violently that seed rises in the water column, but just enough that berry skin begins to float and pour off the non-seed debris. When seed is as clean as possible, pour wet seed onto paper towel and allow to dry. Pick out debris with tweezers. Dry to <38% RH. Store at 4 °C.
Pre-Planting Treatments: Due to small seed size, the easiest method is to sow seed into trays filled with stabilized medium plugs (Q-plugs). Trays are sealed inside plastic bags and placed into refrigeration at 1 to 3 °C for 120 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.
Q-plugs are lightly covered with nursery grit. Seedlings are transplanted to target containers approximately 3 weeks following removal from stratification.
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 fairly uniform and is usually complete in 2 weeks. Following germination (while still in Q-plugs), plants are fertilized with soluble 12-2-14-6Ca-3Mg at 75 to 100 ppm for 2 weeks.
Length of Establishment Phase: 2 to 3 weeks
Active Growth Phase: Plants grow rapidly following establishment, and will need to be pruned multiple times approximately 2 to 3 months following transplanting into the target container. 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: 15 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: 2 to 3 weeks
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: R. ursinus has a high fire tolerance and provides forage for wildlife. R. ursinus is a wide spreading shrub/vine and is typically dioecious, where only the female bear fruit. The species can tolerate temperatures as low as -17 °C (0 °F) and has a moderate to high water requirement.
References: Bonner FT, Karrfalt RB, Nisley RG, editors. 2008. The woody plant seed manual. Washington (DC): USDA Forest Service. Agriculture Handbook 727. 1223 p.


Calscape. nd. Pacific blackberry Rubus ursinus. California Native Plant Society. URL: http://calscape.org/Rubus-ursinus-(Pacific-Blackberry) (accessed 12 Oct 2018).

Dorena Genetic Resource Center Propagation Records, unpublished.

USDA Natural Resources Conservation Service. Rubus ursinus Cham. & Schltdl. California blackberry. URL: https://plants.usda.gov/core/profile?symbol=RUUR (accessed 12 Oct 2018).

Citation:

Riley, Lee E.; Smith, Haley S.; Boudreaux, Tanja. 2018. Propagation protocol for production of Container (plug) Rubus ursinus Plants 444 ml (27 in3) container; USDA FS - Dorena Genetic Resource Center Cottage Grove, Oregon. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/07/01). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.