Rubus (parviflorus)

Mark E. Majerus USDA NRCS - Bridger Plant Materials Center 99 South River Road, Rte. 2, Box 1189 Bridger, Montana 59014-9718 (406) 662-3579 (406) 662-3428 (fax) mmajerus@mt.nrcs.usda.gov http://plant-materials.nrcs.usda.gov/mtpmc

---

Family Scientific Name:	Rosaceae
Family Common Name:	Rose Family
Scientific Name:	Rubus parviflorus Nutt.
Common Name:	Thimbleberry
Species Code:	RUPPAR
Ecotype:	Multiple Glacier National Park ecotypes (seed sources) tested. Primary work with NRCS accession numbers 9078267 (Avalanche seed source) and 9078626 (Camas). Both sources from approximately 3,500 feet of elevation from the west side of Glacier National P
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Stock Type:	10 cubic inch containers
Time To Grow:	1 Years
Propagule Processing:	The fruit of this species is quite perishable and should be stored under refrigerated conditions in a ziplock bag or sealed plastic container. Avoid overfilling the container and provide adequate air circulation between the fruit. Process fruit as soon as possible. Fruit processes readily in a DybvigT macerator although the seed is so small that some may escape with the rinsate through the bottom of the machine. Cover the rinsate exit spout with cheese cloth or fine screen to capture the seed. For small lots of fruit, process in a blender with the impeller blades covered with duct tape. Use the pulse cycle to prevent seed damage. Seeds are spread on kraft paper in a warm, dry place for about 24 hours to dry. Finish cleaning over a fanning mill to remove chaff. We store seeds in a paper envelope in a cool basement, although we have no information that this method represents optimum storage conditions.
Pre-Planting Treatments:	We sometimes coat seeds with ThiramT as a sowing pre-treatment, but have no information that this improves germination or subsequent survival. Because of consistently high germination success, we surface sow 2-3 seeds in each 10-cubic-inch container in a well-drained peat-lite mix, irrigate, and then cover the seed with a shallow layer of fine perlite or vermiculite. The seeds are left overnight in a warm environment to imbibe water. The next day, the containers are moved to a cooler maintained at 34 to 37øF and high relative humidity for a 4- to 5-month cold, moist chilling. After chilling the containers are moved to a greenhouse. After 4 to 6 weeks, multiple germinates in a single container are thinned to one seedling, extra seedlings can be transplanted to empty containers with good success.
Hardening Phase:	Bridger hardens-off RUPA in two manners with equal success. The two techniques are used for all containerized plant materials and reflect production scheduling rather than any species-specific need that we have identified. The first method involves moving containerized material (at least 2 months old) started in the greenhouse that winter to an outdoor hoophouse in late spring/early summer. The hoophouse is ventilated but not cooled, and the containers are usually exposed to full sunlight for 2 to 4 weeks early in the season. The hoophouse is then covered with a 50% shade cloth until temperatures cool in the fall. The second option is to move containers to the shadehouse in late summer, allowing 30 to 60 days of hardening prior to winter. The shade is usually removed in late summer/early fall and replaced with clear plastic. The plants harden-offgradually in the hoophouse prior to winter. Bridger is characterized by a high number of solar days that keeps the environment inside the hoophouse relatively mild until winter. In the case of premature and severely cold weather, a small propane heater is used at keep temperatures above freezing.
Length of Hardening Phase:	As a standard practice, we allow a minimum of 30 days of hardening off prior to killing frost, 60 days is preferred.
Harvesting, Storage and Shipping:	Since nearly all containerized stock is shipped dormant from Bridger in the spring, we overwinter all material in an outdoor hoophouse. The hoophouse is ventilated when temperatures reach 35 to 40øF and heated to maintain a temperature of 5 to 10øF. Containers as small as 10-cubic-inch overwinter well this way. The containers are placed on 2 inches of pea gravel and arranged in a side-by-side pattern. The stock is watered over the fall and winter as needed. If temperatures in the spring are too warm to assure dormancy, plant material that is designated for dormant spring planting is moved to a walk-in cooler (34 to 37øF, 80+% relative humidity) until shipping. Plants may be shipped with or without containers in heavy waxed boxes by priority ground mail (avoid weekend holdover at post offices).
Length of Storage:	Dormant containerized plants hold well in a cooler for several weeks.
Other Comments:	We attribute poor success with field plantings of RUBPAR at Bridger to our heavy textured soils. The small seedlings appear to have difficulty emerging through the soil crust. Shallow sowing and the use of excelsior mat did not improve emergence noticeably (approximately 5 to 10% of the germination obtained in commercial media in the greenhouse). Propagation beds should be rototilled to break up soil clods and surface crust. We lightly firm the seedbed with a roller prior to sowing with a belt seeder at 25 to 50 seeds per linear foot. Sow seed at <0.25 inches and then mulch the bed until covered with small, light organic mulch (possibly sawdust). In small trials with greenwood terminal stem cuttings, RUPA rooted better than 80% in a traditional propagation system with 1,000 ppm IBA, bottom heat, and intermittent mist. It was also observed that the same type of cutting rooted well in a beaker of water with 1,000 ppm IBA in solution. Adequate rooting for transplanting occurred within 6 to 8 weeks.

Citation:

Scianna, Joe. 2003. Propagation protocol for production of Container (plug) Rubus parviflorus Nutt. plants 10 cubic inch containers; USDA NRCS - Bridger Plant Materials Center Bridger, Montana. 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.