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Protocol Information

Native Plant Nursery
USDI NPS - Glacier National Park
West Glacier, Montana 59936
(406) 888-7835

Family Scientific Name: Cupressaceae
Family Common Name: Cedar family
Scientific Name: Thuja plicata Donn.
Common Name: Western redcedar
Species Code: THUPLI
Ecotype: Cedar/Hemlock forest, 1100m elev. Avalanche, Glacier National Park, Flathead Co., MT.
General Distribution: T. plicata is found from Alaska to northern California, east to southeast B.C., northern Idaho, and northwest Montana. It is very shade tolerant and commonly occurs as a dominant or codominant forest species on low elevation (0 to 2000m) moist sites with cool summers and wet, mild winters. It grows on a variety on soil types.
Propagation Goal: Plants
Propagation Method: Seed
Product Type: Container (plug)
Stock Type: 172 ml conetainers
Time To Grow: 10 Months
Target Specifications: Stock Type: Conetainer seedling
Height: 17 cm
Caliper: 6 mm
Root System: Firm plug in conetainer.
Propagule Collection: T. plicata flowers in late May to June and cones ripen from late August to October. Seeds are collected when cones are brown, but before scales begin to reflex. Seeds are collected using a pruning pole and canvas tarp. Cone bearing branches are cut and fall on tarp below. Cones are hand pulled off branches and stored in paper bags.
Propagule Processing: Seeds are easily extracted from opened cones using a tumbler. Do not dewing the seeds.
Seeds are stored at 0C in sealed containers.
Seed longevity is up to 5 years.
Seed dormancy is classified as non dormant.
% Purity:100%
% Germination:52 to 81%
Pre-Planting Treatments: Seeds are placed in a 48 hour running water rinse. Do not bleach treat seeds. Seeds are placed into a 45 to 65 day cold, moist stratification. Seeds are placed in fine mesh bags and buried in moist peat moss in ventilated containers under refrigeration at 3C.
Growing Area Preparation/
Annual Practices for Perennial Crops:

Greenhouse and outdoor nursery growing facility.
Sowing Method: Direct Seeding. Seeds are lightly covered with medium.
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 1 gram of Osmocote and 0.20 gram of Micromax per 172 ml conetainer.
Containers are irrigated thoroughly after sowing and greenhouse temperatures are maintained at 21 to 23 C day and 15 to 18C night. Plants are grown under greenhouse conditions for 16 weeks and are then moved to the outdoor shadehouse for the remainder of the growing season.
Establishment Phase: Germination was complete in 3 weeks. Seedlings are thinned at the birdcage stage.
Seedlings are fertilized with Conifer Starter 7-40-17 liquid NPK at 50 ppm for 4 weeks after true leaves emerge.
Length of Establishment Phase: 10 weeks
Active Growth Phase: Seedlings reach the rapid growth stage 10 weeks after germination. Average height was 14 centimeters 4 months after germination. Growth of seedlings is maximized when air temperatures are maintained at 20 to 21C. Plants attained root-tightness 5 months after germination.
Plants were regularly fertilized with 20-7-19 liquid NPK at 200 ppm.
Length of Active Growth Phase: 16 weeks
Hardening Phase: Plants are fertilized with 10-20-20 liquid NPK at 200 ppm in early fall. Irrigation is gradually reduced through September and October. One final irrigation is applied prior to winterization.
Length of Hardening Phase: 8 weeks
Harvesting, Storage and Shipping: Total Time To Harvest: 10 months
Harvest Date: September
Storage Conditions: Overwinter in outdoor shadehouse under insulating foam cover and snow.
Length of Storage: 5 months
Outplanting performance on typical sites: Outplanting Site: Avalanche, Glacier National Park, MT.
Outplanting Date: September
Other Comments: 3L (1 gallon ) containers can be produced in 1.5 years with the seedlings averaging 23 centimeters in height and 1.0 cm in caliper.
9L (3 gallon) container seedlings can be produced in 2.5 to 3 years.

Vegetative Propagation Method: Pre-Rooting, not tried.
Type of Cutting: Fall semi-hardwood tip cuttings, treated with 3000 ppm IBA talc, taken in early October, under mist with 50:50 (v:v)sand:peat rooting medium and bottom heat at 21 C have yielded 91% rooting in 8 weeks.
In closed canopies, western redcedar reproduces naturally from layering, and rooting of live branches which have fallen on wet soil.
Deer and elk browse the foliage and bears feed on the sapwood.

References: Flora of the Pacific Northwest, Hitchcock and Cronquist, Univ. of Washington Press, 7th printing, 1990.

Seed Germination Theory and Practice, Second Edition, Deno, Norman, published 1993.

Glacier Park Native Plant Nursery Propagation Records, unpublished.

The Reference Manual of Woody Plant Propagation, Dirr and Heuser, Varsity Press, Inc., 1987.

Seeds of the Woody Plants of the U.S., Agriculture Handbook #450, U.S.F.S., Washington DC.

Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination, Baskin and Baskin, Academic Press, 1998.

Propagation of Pacific Northwest Native Plants, Rose,R., Chachulski, C., and Haase, D. Oregon State University Press,1998.

Luna, Tara; Hosokawa, Joy.; Evans, Jeff.; Wick, Dale. 2008. Propagation protocol for production of container Thuja plicata Donn. plants (172 ml conetainers); USDI NPS - Glacier National Park, West Glacier, Montana. In: Native Plant Network. URL: http://www.nativeplantnetwork.org (accessed 28 August 2015). Moscow (ID): University of Idaho, College of Natural Resources, Forest Research Nursery.