Doom on Broom: SYRCL Sweeps Away Scotch Broom 

by Riley Endries

On March 29, 2025, SYRCL assembled a crew in the dappled morning sunlight, breaching the canopy in the South Yuba Recreation area campsite. Shovels leaned against shoulders, gloved hands holding weed-pulling wrenches, and a hopeful determination in the air, 17 volunteers shared their excitement for beautiful weather and a chance to come together to cultivate healthy forests.

Around them, oaks, madrones, and kit-kit-dizze (aka mountain misery, aka bear clover) speckled the sparse understory. Occasionally, this mosaic of native plants was interrupted by dense pockets of spindly, chaotic bushes that sometimes reached over their heads: Scotch broom (Cytisus scoparius).

This plant was what brought everyone together.  

SYRCL’s AmeriCorps Restoration Coordinator, Riley Endries, explained to the group that Scotch broom is an incredibly invasive plant throughout the Sierra Nevada; it crowds out native plants by producing excess nitrogen in the soil. The bush is unpalatable to ungulates (e.g. deer, elk, cows, etc.), so it grows quickly and aggressively, unchecked in our forests, reaching heights of 5-10 feet. Dense, mature stands of broom substantially increase the biomass of the sunny areas where they grow, and they have great potential to act as a ladder fuel, allowing low intensity wildfires to burn taller and reach tree canopies. Scotch broom also shades out plants in the understory.

With that background in mind—and a short demonstration on how to use a weed wrench to pull out the bushes—the crew of 18 worked for 4 hours and covered about 9.5 acres of public land. They pulled hundreds of plants, helping to restore the native vegetative community of the campground, trailhead, and parking lot. 

Photos before and after pulling a big clump of Scotch broom. 

You too can make a difference in our watershed by removing Scotch broom!  

How to identify the plant:  

More photos and photos available on the Calflora website

If you have driven around Nevada City, chances are you have passed Scotch Broom flourishing in the disturbed soils around roads. It is a perennial shrub in the pea family (Fabaceae) with bright yellow flowers that attach to the joints of the stem. The young branches and stems of Scotch broom grow rather linearly, have longitudinal ridges, and are green and photosynthetic. As the bush ages, its ratio of woody to green material increases and the main stem of large bushes is usually brown.  

How to remove Scotch broom: 

• Lopping: Regeneration is low if Scotch brooms are lopped near the base of the plant during the driest part of the season and when all of their energy is going into flower and seed production. Lopping should take place when the broom is in bloom from April-May or at the end of the dry season from August-September. Drought stressed plants will usually perish after lopping.  When care should be taken to minimize erosion on steep slopes, lopping can be preferable.

• Hand pulling: When soils are soft after spring rain, young Scotch broom can be pulled by hand. Be sure to remove as much of the root system as possible, as they can develop a deep tap root and wide-reaching runners. Do your best to minimize soil disturbance around the target plant; Scotch brooms germinate best in disturbed soil, and you want to give native vegetation the best chance to outcompete the broom. Do not move the plants if they have developed seeds, as you risk spreading the seeds to uninfected area! 

Volunteers work together to pull broom from hillside. 

• Tools: Weed pullers or weed wrenches clamp at the base of the broom plant and give the puller a mechanical advantage from better leverage. Multiple local agencies have pullers available to rent or borrow. Organizations that lend out weed pullers: SYRCL, Fire Safe Council of Nevada County, Bear Yuba Land Trust, Sierra Streams Institute, and Wolf Creek Community Alliance. See this video for a demonstration on how to use a weed puller:

• Chemical: According to the USDA, “Herbicides are effective in gaining initial control of a new invasion (of small size) or a severe infestation, but are rarely a complete or long-term solution to invasive species management.” (Zouhar, 2005). Herbicide use should be applied sparingly with proper research and never applied during the wet season, as rain spreads herbicide. 

• Protect the soil: Only pull brooms when the soil is wet to minimize disturbance. Scotch broom thrives in disturbed soils, so tap down soil after pulling and, even better, scatter native seeds in the disturbed area. Native grasses work well here, as they quickly grow, stabilize soil, and provide nutrients. If worried about erosion, you can add mulch and rocks. 

Best time to pull: March through May, before the plant develops seeds and while the ground is soft.  

Scotch broom typically develops seeds in pea-like pods by June and July, depending on elevation and climatic conditions. One should remove the plants before the risk of spreading seeds arises; that is typically during late March to April in inland California, as the plants are still in flower, but the ground is soft and pulling is easier. Some studies suggest the seeds stay viable for 30 years and potentially as long as 80 years. They also have a high viability rate (One study in El Dorado National Forest found 98% of fresh seed is viable (Bossard, 1993)) 

How to dispose of the pulled broom: 

• Scotch broom can be burned on private land; however, consult the fire department for guidance in burning brush piles. A high enough intensity burn will kill the seeds and prevent re-seeding.
• Chipping is okay if the broom has not set seed yet 
• Burying the scotch broom deep underground will prevent the seeds from having the necessary conditions to germinate in their lifetime 
• Bring removed Scotch broom to the dump 

Upcoming community events:

Besides SYRCL, the following organizations often organize Scotch broom pull events. Please sign up for their newsletters or follow them on social media to find out when their next event may be.

• California Native Plant Society Redbud Chapter
• Bear Yuba Land Trust
• Wolf Creek Community Alliance
• Tahoe National Forest

Resources where people can access more information: 

• UC Davis Scotch broom report: https://wric.ucdavis.edu/information/crop/natural%20areas/wr_C/Cytisus.pdf 
• Quick guide to controlling Scotch broom in PNW: https://www.invasive.org/gist/moredocs/cytsco01.pdf 
• USDA Extensive Report on BOTANICAL AND ECOLOGICAL CHARACTERISTICS of Scotch broom and management: https://www.fs.usda.gov/database/feis/plants/shrub/cytspp/all.html#GENERAL%20BOTANICAL%20CHARACTERISTICS 
• Zouhar, Kris. 2005. Cytisus scoparius, C. striatus. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://www.fs.usda.gov/database/feis/plants/shrub/cytspp/all.html [2025, April 14].