RNGR.net is sponsored by the USDA Forest Service and Southern Regional Extension Forestry and is a colloborative effort between these two agencies.

U.S. Department of Agriculture USDA Forest Service Southern Regional Extension Forestry Southern Regional Extension Forestry

Skip to content. | Skip to navigation

The Forest Service National Center for Reforestation, Nurseries, and Genetic Resources (RNGR) is a leading source of technical information for nurseries and land managers regarding production and planting of trees and other native plants for reforestation, restoration, and conservation.

 
NPN Protocol Details Image

Cirsium (occidentalis)

Betty Young
Nurseries Sr Manager
Bldg 201, Fort Mason
San Francisco, California 94123
415-331-6917
415-331-7521 (fax)
byoung@ggnpa.org

Family Scientific Name: Asteraceae
Family Common Name: Sunflower Family
Scientific Name: Cirsium occidentalis (Gray)
Common Synonym: Cirsium californicum (Gray)
Common Name: Cobweb Thistle
Species Code: CIROCC
Ecotype: Marin County, California
General Distribution: C. occidentalis is found in sandy places, from Mendicino County to Monterey County and San Miguel, Santa Rosa and Santa Cruz islands, California.
Propagation Goal: plants
Propagation Method: seed
ProductType: Container (plug)
Stock Type: Deepot 16
Time To Grow: 0
Target Specifications: Height: N/A<br> Caliper: N/A<br> Root System: Firm plug in container.
Propagule Collection: Seeds are collected between April 1st and June 1st.
Mature inflorescences are brown and pappus is silver and beginns to fluff out. Collect early to avoid seed predatiob by weevils.
Propagule Processing: Seed Cleaning: Seeds are pulled from heads and rubbed over a screen to remove the pappus.
Storage Conditions: Seeds are kept dry and stored in a refrigerator.
Seeds/gram: 111
Pre-Planting Treatments: Soak fresh seeds overnight in frsh water and stratify for 2 weeks or until seeds begin to germinate.
Growing Area Preparation/
Annual Practices for Perennial Crops:
Fully Controlled Greenhouse.
Sowing Method: Transplanting Germinants.
8 grams of seeds are sown per flat containing Sunshine Mix #4 Aggregate Plus (peat moss, perlite, major and minor nutrients, gypsum, and dolomitic lime).
Seeds are covered with media.
Flats are watered in with an automatic irrigation system and misted as needed. Remove from mist as soon as first leaves appear; Cirsium leaves rot easily.
Seeds are sown on July 1st.
% Germination:50%
Establishment Phase: Seeds germinate 14 days after sowing.
Seedlings are transplanted 14 days after germination to individual containers 2"x7" tubes (Deepot 16) containing standard potting mix of peat moss, fir bark, perlite, and sand.
Transplant Survival averages 90%.
Length of Establishment Phase: 1 month
Active Growth Phase: Fertilize with Nutricote (NPK 13-13-13) 3 months after transplanting. Be careful not to over fertilize; lush foliar growth attracts aphids.
References: A California Flora and Supplement, Munz, P., University of California Press, Berkeley and London, 1973.

Citation:

Young, Betty. 2001. Propagation protocol for production of Container (plug) Cirsium occidentalis (Gray) plants Deepot 16; San Francisco, California. 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.