Juniperus (scopulorum)

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

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Family Scientific Name:	Cupressaceae
Family Common Name:	Juniper Family
Scientific Name:	Juniperus scopulorum Sarg.
Common Name:	Rocky Mountain juniper
Species Code:	JUNSCO
Ecotype:	Numerous northern Plains seed sources from Montana, North Dakota, and Wyoming. Currently propagating NRCS accession number 9081849, an ecotype from the Old Faithful area of Yellowstone National Park.
Propagation Goal:	plants
Propagation Method:	seed
ProductType:	Container (plug)
Stock Type:	10- to 40-cubic-inch conetainers
Time To Grow:	0
Propagule Collection:	Fruit (berry-like cone) is collected by hand in late fall to mid-winter. Avoid collecting fruit with evidence of insect damage (small exit holes). Maturation requires two years, with both 1-year and 2-year fruit found simultaneously on the same plant. Mature fruit is dark blue to nearly black in color. Store fruit in sacks in a cooler maintained at 34 to 37øF and 80+% relative humidity prior to cleaning. Do not allow skin to dry out and become tough prior to cleaning. Allow adequate air circulation to prevent conditions that result in molding of fruit.
Propagule Processing:	Fruit pulp is very sticky and requires presoaking in a weak lye solution or theuse of citrus handcleaner plus pumice during processing. Place 3- to 5-lb lots of berries in a Dybvig macerator at a time. Add citrus handcleaner and water at intervals during processing to remove the pulp and sap from the seed. Continue adding cleaner and water until the seed appears clean and no longer feels sticky. Float off light seed and debris by repeatedly rinsing the seed with water. Spread the seed on kraft paper in a warm dry location and allow to dry for 24 to 48 hours.Store in paper envelopes or woven cotton sacks in a cool environment such as a basement.
Pre-Planting Treatments:	Various durations of warm moist stratification followed by 6 to 8 months of cold moist chilling is the standard dormancy breaking recommendation. The use of 30 to 60 minutes of acid scarification prior to the aforementioned treatment has improved germination in limited trials as the PMC. A cold:warm:cold schedule is also reported to improve germination, although it does not shorten the dormancy breaking period.
Hardening Phase:	Move containerized material (at least 2 months old) started in the greenhouse that winter to an outdoor hoophouse in late spring/early summer (i.e. "finish" the plants in the hoophouse). 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. Another option is to finish container plants and rooted cuttings in the greenhouse and then move them 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-off gradually 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 containers in an unheated hoophouse. The hoophouse is ventilated when temperatures reach 35 to 40øF and heated to maintain a temperature of 5 to 10øF. One and even 2-year stock overwinters well this way in as small as 10-cubic-inch conetainers. 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).
Other Comments:	We have better and more consistent germination with container production of this species than bareroot, possibly because of the controlled environment during the dormancy breaking period. One of our most hardy and useful conservation plants, this species presents numerous propagation obstacles - but is worth the effort.

Citation:

Scianna, Joe. 2003. Propagation protocol for production of Container (plug) Juniperus scopulorum Sarg. plants 10- to 40-cubic-inch conetainers; USDA NRCS - Bridger Plant Materials Center Bridger, Montana. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/07/02). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.