Physocarpus (capitatus)

Lee Riley Horticulturist USDA FS - Dorena Genetic Resource Center 34963 Shoreview Road Cottage Grove, Oregon 97424 541-915-7324 541-767-5709 (fax) lee.riley@usda.gov

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Family Scientific Name:	Rosaceae
Family Common Name:	Rose
Scientific Name:	Physocarpus capitatus
Common Name:	Pacific ninebark
Species Code:	PHCA11
Ecotype:	Siuslaw and Willamette National Forests, Oregon
General Distribution:	Pacific ninebark is scattered to common west of the Cascades and often abundant in wet areas and on steep north slopes of the coastal mountains. Habitats include streambanks, lake margins, and swampy areas or openings in moist woods. Occasionally, Pacific ninebark is found in coastal marsh lands and meadows or at drier shrubby sites. Pacific ninebark occurs primarily west of the British Columbia Coast, Cascade, and Sierra Nevada Mountain Ranges from extreme southeast Alaska to central California
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.
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 30 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 weeks
Active Growth Phase:	Plants grow rapidly following establishment, and may need to be top-pruned approximately 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:	Wetland classification: FACW It is particularly valuable for streambank and lakeshore stabilization applications
References:	Dorena Genetic Resource Center Propagation Records, unpublished. Gonzalves P, Darris D. 200. Plant fact sheet: Pacific ninebark Physocarpus capitus (Pursh Kuntze). Corvallis (OR): USDA Natural Resources Conservation Service, Plant Materials Center. URL: https://plants.usda.gov/factsheet/pdf/fs_phca11.pdf (accessed 10 Oct 2018).

Citation:

Riley, Lee E.; Klocke, Allison. 2018. Propagation protocol for production of Container (plug) Physocarpus capitatus Plants 444 ml (27 in3) container; USDA FS - Dorena Genetic Resource Center Cottage Grove, Oregon. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2025/02/24). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.