Dominating Scotch Broom with success

By Al Schmauder and Marianne Lincoln

200 years ago, it wasn’t here. The prairies of Western Washington were rife with flowers of multiple varieties. Then Mrs. Tolmie planted the Scotch Broom she imported to remind her of home. The brush grew tall and flourished, dropping seeds into the soil that can last 30 years or more. It literally did better here than in Scotland. There were no natural enemies in Washington to keep Scotch Broom in check.

Then in the 1950’s & 60’s, and the Interstate Highway System. The Washington Department of Transportation saw the dollar signs. A plant that spread so well would be perfect along the displaced soils from all the new freeways. Interstate 5 became of corridor of Scotch Broom.

What we all forgot to do was figure out how best to get rid of it. So now, Al Schmauder, Dr. Derek Faust and a few other watershed stewards around Lakewood decided to do a test. They compared patches of Scotch Broom that were removed in several different ways.

You can
1) Pull it up by the root by hand or with a pulling tool
2) Burn it in a controlled burn
3) Cut it down

Mature Scotch Broom can be over ten feet tall. You cannot easily pull those out with brute strength. What they found in their research is that pulling leaves a hole in the ground, loosens the soil, and makes it easier for the seeds resting there to germinate.

On the other hand, using a saw to cut them leaves the root intact, but it rarely resprouts. The surrounding ground is not loosened so the germination is not triggered. Over a three-year period, there were far less plants emerging in the cut down areas.

Burning is not an easy task, as it is difficult to do a controlled burn and Scotch Broom burns hot, so it can easily become a nightmare. Even so, in a successful burn, there are still frames of plants to remove which can disturb the soil. The process or burning does also enhance the soil with nutrients, making the ground bloom out with many species of plant life, eventually including the Scotch Broom again.

So, the best answer is, cut it down. Like all the developers know, a bulldozer, grass seed, and constant mowing also can do the trick, especially with all the impervious surface they add to the process. Roads and roof tops do displace Scotch Broom, as well as many other biological species.

Here are the directions from Al Schmauder. [15 May 2026, Al_schmauder@hotmail.com]

The easy way to remove mature Scotch Broom.

Many people pull out Scotch Broom using a weed puller. This works but it has drawbacks:
• It takes strength to get the puller’s jaw around the root and to pull the plant out.
• The ground around the plant is loosened and disturbed when the roots are pulled out. This encourages new plants to reseed.
• Pulling takes time. It is hard to get to the tap root with large plants.

A better way is to use a battery powered Sawzall or reciprocating saw with a 6-inch blade with course teeth. This blade is made to cut branches. Cut the tap root just under the ground below where the branches start.

The benefits are:
• One does not need much strength. The saw does the work. Grandma can do this. (If she can still bend down.)
• The ground is not disturbed.
• It is fast. It takes an average of 15 seconds per plant.
• The kill rate is almost 100%. Especially when the plants are in full bloom.

How to Tips:

• Locate the tap root with your fingers so you know where to cut.
• Check to see if there are any big rocks to avoid or cut around.
• Always keep the saw trigger locked when not actively cutting. BE SAFE.
• Use a sharp lopper for tap roots ½ inch thick or less & cut below the ground.

Cost of saw.

I use a Ryobi saw with an 18-volt battery. Home Depot offers sales on them with one battery and a charger for about $100. A 6-inch blade cost about $6.

Compared to a Scotch Broom pulling tool which costs from $129 to nearly $200, that is a bargain. A guy with a bulldozer will cost far more.

In 30 minutes, one can cut down about 100 large plants.