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Juniperus (communis)

Tara Luna
USDI NPS - Glacier National Park
West Glacier, Montana 59936
(406) 888-7835

Family Scientific Name: Cupressaceae
Family Common Name: Cedar family
Scientific Name: Juniperus communis L.
Common Name: Common juniper
Species Code: JUNCOM
Ecotype: Rock outcroppings, Sun Point, 1600 m elevation, Glacier National Park, Glacier Co., MT.
General Distribution: J. communis occurs in lowland forests to mountain valleys and open rocky slopes; from Alaska to California, east to Newfoundland and Greenland. It is found throughout Europe, northern Asia and Japan.
Propagation Goal: plants
Propagation Method: vegetative
ProductType: Container (plug)
Stock Type: 800 ml containers
Time To Grow: 15 Months
Target Specifications: Height: 7 cm<br> Caliper: 5 mm<br> Root System: firm plug in 800 ml container.
Propagule Collection: Cuttings are collected from healthy field plants in early to mid May.
Propagule Processing: Cuttings are kept moist and under refrigeration prior to pretreatment. It is best to treat cuttings immediately after collection.
Pre-Planting Treatments: Vegetative Propagation Method: Pre-rooting.
Type of Cutting: Semi-hardwood stem cuttings
Cuttings were recut after collection, with 1/2 of basal leaves removed. This provides some wounding that promotes rooting.Terminal buds are removed and cuttings are treated with 2 minute Domain fungicide bath to remove surface pathogens. Cuttings were treated with 8000 ppm IBA and placed in mist bed with bottom heat set at 21C. Cuttings were 13 cm in length, 5 mm in diameter.
Cuttings taken in fall (October to November) or winter (January or February) treated with 3000 to 8000 ppm IBA have been rooted to high percentages by many commercial growers.
Rooting of Juniperus communis is considered best after stock plants have been subjected to several hard frosts or freezes.
Hand watering rooting medium is preferable to using intermittent mist to avoid fungal development on the needle-like leaves.
Rooting %: Semi-hardwood stem cuttings: 26%
Hardwood stem cuttings: 17% to 35%
Growing Area Preparation/
Annual Practices for Perennial Crops:
The outdoor mistbed has automatic intermittent mist that is applied at 6 second intervals every 6 minutes. Too frequent misting will result in leaf and stem rot. Bottom heat is maintained at 21C with heating cables buried 12 cm beneath rooting medium. Rooting medium is 50% perlite and 50% sand. Mistbed is covered with shadecloth during rooting.
Establishment Phase: Time to Transplant: 12 weeksCuttings that were pre-rooted were lifted out of mistbed after adequete root systems were formed. Roots generate from the nodes below the surface of the rooting media.
Cuttings were not misted frequently as this causes needle decay.
Length of Establishment Phase: 12 weeks
Active Growth Phase: After cuttings were lifted from the mistbed, they were potted into 800 ml containers. Growing medium used is 6:1:1 milled sphagnum peat, perlite, and vermiculite with Osmocote controlled release fertilizer (13N:13P2O5:13K2O; 8 to 9 month release rate at 21C) and Micromax fertilizer (12%S, 0.1%B, 0.5%Cu, 12%Fe, 2.5%Mn, 0.05%Mo, 1%Zn) at the rate of 5 grams of Osmocote and 2 grams of Micromax per container. Cuttings were irrigated after potting and placed in the shadehouse for 4 weeks.
After establishment in the shadehouse, plants were moved to full sun exposure in the outdoor nursery.
Length of Active Growth Phase: 16 weeks
Hardening Phase: Plants are fertilized with 10-20-20 liquid NPK at 200 ppm during August and September. Plants were given one final irrigation prior to winterization.
Length of Hardening Phase: 4 weeks
Harvesting, Storage and Shipping: Total Time to Harvest: 1.3 years for cuttings
Harvest Date: September
Storage Conditions: Overwinter in outdoor nursery under insulating foam cover and snow.
Length of Storage: 5 months
Other Comments: Seed Propagation: Berry-like cones are collected in late fall by handpicking, stripping or shaking the cones from the shrubs on a canvas tarp. Fruit is collected when berry-like cone has matured to dark blue and is somewhat soft in consistency> The cones should be two years old at this stage and distinguishable from 1 yr old cones which are covered with a powder blue bloom and are hard in consistency.
Seeds/Kg: 80,300/kg.
There are usually 1 to 4 seeds per cone. Seeds are brown at maturity.
Seed longevity: up to 10 years at 1 to 3C in sealed containers.
Seed dormancy is classified as physiological dormancy.
Seed Treatments: 48 hour running water rinse; 60 day warm, moist stratification followed by 90 cold, moist stratification. Juniper seed has both physiological and seed coat dormancy which are often difficult to overcome. The prolonged warm/cold stratification treatment is effective in producing sizable seedlings in 2 years.
References: Flora of the Pacific Northwest, Hitchcock and Cronquist, University of Washington Press, 7th printing, 1981.
Seeds of the Woody Plants in the United States, Agriculture Handbook No. 450, U.S.F.S., Washington D.C., 1974.
Glacier Park Native Plant Nursery Propagation Records, unpublished.
The Reference Manual of Woody Plant Propagation, Dirr and Heuser, Varsity Press, 1987.


Luna, Tara; Evans, Jeff; Hosokawa, Joy. 2008. Propagation protocol for production of Container (plug) Juniperus communis L. plants 800 ml containers; USDI NPS - Glacier National Park West Glacier, Montana. In: Native Plant Network. URL: http://NativePlantNetwork.org (accessed 2021/06/17). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

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