February Invasive Weed of the Month: Scotch Broom

Scotch broom in late-winter, before it gets it’s familiar yellow blooms.

Scotch broom is a wide-spread invasive weed in our community. You have probably noticed large stands of it along our rural roads and highways, in pastures and in forests. Now is a great time to start managing Scotch broom.

Scotch broom was originally introduced as an ornamental shrub along highway corridors and, in western Oregon, as a dune stabilizer. It is now one the most widespread forest weed species.

Scotch broom is an attractive evergreen shrub. It has many slender, erect, dark green branches with small leaves up to half an inch long. It grows from 3 to 10 feet in height. Beginning in late April or early May, it is covered with bright yellow, pea-like flowers. The flowers mature to flattened seed pods that contain up to a dozen seeds each. Dried pods will crack and pop open in mid summer and eject the seeds a short distance.

Why Should I Care about Scotch Broom?

Scotch broom is found all around Clackamas County.

Scotch broom is an opportunistic and aggressively prolific invasive plant. A single plant can produce well over 20,000 seeds that last in the soil for more than 30 years (some estimates are as long as 80 years).

Scotch broom easily invades disturbed sites, natural areas, dunes, and forest lands. This weed displaces native and beneficial plants and smothers tree seedlings, hampering reforestation efforts. It causes loss of grassland and open forest habitat. Flowers and seeds are toxic to humans and most animals. Scotch broom creates highly flammable fuels increasing wildfire danger. Control costs for this weed exceed $47 million annually.

How Can I Control Scotch Broom?

Remove Scotch broom before seed sets!

Scotch broom can be controlled by various methods depending upon the severity and the location of the infestation. Plants can be pulled when they are small and dug when they are larger. They can be cut between flowering and seed production and stumps can be treated with herbicides. Do not put plants with seed pods in compost or yard waste. They should be bagged and placed in the garbage. Also, do not burn plants with seed pods because when exposed to fire, the seeds burst from their seed pods.

If you are looking for a yellow blooming bush for spring color, rather than planting Scotch broom, consider the native Tall Oregon Grape or the ornamental Forsythia hybrid.

Springtime is a great time to control Scotch broom by pulling. Moist soil makes it easier to pluck young broom plants out of the ground. For older, more mature plants, try using a weed wrench. The Clackamas Soil and Water Conservation District has Weed Wrenches in a variety of sizes. They are available to loan at no charge. Contact us at 503-210-6000 to reserve your weed wrench today.

For additional information about Scotch broom, check out the WeedWise Scotch Broom Best Management Practices!

 

 

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