Asteraceae (Isocoma)

Protocol Information for:

Label_title:
Isocoma (menziesii)

Family Names:

Family Scientific Name:
Asteraceae

Family Common Name:
Sunflower Family

Scientific Names:

Genus:
Isocoma

Species:
menziesii

Scientific Classification:

Scientific SubSpecies:

Species Authority:
(Hook. & Arn.) Nesom

Scientific SubAuthority:

Authors:

Mike Herrera

Common Synonym:

Genus:

Species:

Synonym Classification:

Synonym SubSpecies:

Species Authority:

Synonym SubAuthority:

Other Information:

Common Name:
Coast Goldenbush

Species Code:
ISOMEN

Ecotype:
Catalina Island, California

General Distribution:
Coast Goldenbush is found throughout southern California and the Channel islands. On Catalina Island, it inhabits beaches, flats, sea cliffs, and dry sunny hillsides.
There are 4 botanical varieties on Catalina island: var. decumbens,menziesii, sedoides, and vernonioides.

Known Invasiveness:

Propagation Goal:
plants

Propagation Method:
seed

Product Type:
Container (plug)

Stock Type:
4 inch containers

Grow Time:
5 Months

Target Specifications:
Height: N/A
Caliper: N/A
Root System: Firm root plug in container.

Propagation Collection:
Achenes are hand collected when they are fully matured. We have collected seeds in November and early December. Seeds are small, grey to tan, and with a fine pappus.

Propagation Processing/Propagule Characteristics:
Achenes dry in paper bags in a warm, dry room. We clean the seeds by running dry fruits through a large screen to remove large debris. We sift with a US Standard test sieve (#14) to remove smaller debris. Next, we use a seed blower at 1.5 to 3.5 settings toseparate seeds from pappus and bracts.
After seeds have been cleaned, they are stored under refrigeration in air tight glass containers at 40 F and 40% RH. With 8 collections, seeds average 0.13 grams per 100 seeds.

Pre-Planting Propagule Treatments:
We have used a 3 minute Physan fungicide soak or a 3 minute 5% bleach solution to surface sterilize seed coats prior to testing or sowing.
Germination percentages have ranged from 0 to 27%.

Growing Area Preparation / Annual Practices for Perennial Crops:
The James H. Ackerman Native Plant Nursery is located on Catalina Island off the coast of southern California. From 1993 to 2004, the average maximum and minimum temperatures have been 75.4 F and 46 F, with an average of 361 frost free days per year and annual rainfall of 14 inches.
The facility is comprised of shade houses, mist propagation house, and an outdoor growing compound. All propagation environments are utilized at different stages of seedling growth to provide for the variance in temperature and shading requirements needed during the growing season. We irrigate all containers with an overhead emitter system in the shadehouses and use a drip system or hand water in the outdoor nursery.

Establishment Phase:
Seeds are germinated during winter months in a shadehouse were they remain for several weeks. Flats and containers are filled with a 1 inch layer of special seed germination mix of 1:1 (v:v) Sunshine Professional Growing Mix and sand on top of 4:1:1 (v:v:v) peat, perlite, and organic compost. We incorporate Osmocote time release fertilizer (9 month release rate) (14 N:14P2O5:14K2O) at the rate of « cup per 0.75 cubic yard of medium. Seeded flats are watered with an overhead emitter system as needed.

Length of Establishment Phase:
2 months

Active Growth Phase:
After seedlings are well established and have at least 2 true leaves, they are transplanted into containers filled with a growing medium of 4:1:1 (v:v:v) peat, perlite, and organic compost. Osmocote time release fertilizer (9 mo release rate) (14 N:14P2O5:14K2O) is incorporated into the medium at a rate of of « cup per .75 cubic yards of medium. Following transplanting, seedlings are moved to another shadehouse with more temperature variance where they remain for several weeks.
We shift 4 inch container plants once they are root tight to #1 treepots (173 cubic inches) by the end of June. We top prune as needed to encourage branching.

Length of Active Growth Phase:
3 months

Hardening Phase:
Any nursery stock grown under shadehouse conditions are hardened by placing them in full sun exposure for a minimum of 2 weeks prior to outplanting.

Length of Hardening Phase:
2 to 4 weeks

Harvesting, Storage and Shipping:
Containerized seedlings are over wintered directly in the open growing compound.

Length of Storage:
Variable; depends on out planting date.

Guidelines for Outplanting / Performance on Typical Sites:

Other Comments:

References:

Citation:
Herrera, Mike. 2006. Propagation protocol for production of Container (plug) Isocoma menziesii (Hook. & Arn.) Nesom plants 4 inch containers; Catalina Island Conservancy Avalon, California. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2026/05/27). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

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