Giving Scotch broom a clean sweep from the North Island
PORT McNEILL — The local Communities in Bloom Society devoted a day to sweeping Scotch broom from its town.
But the effort will take a lot more than one day.
“A mature plant can produce 20,000 to 30,000 seeds, and each seed remains viable for 80 years,” said Mike DesRochers, a silvaculture expert with the Ministry of Forests in Port McNeill. “Without using herbicides, the best treatment is to go back every year the rest of our lives and cut it.”
Communities in Bloom organizer Sharon Barratt was pleased her volunteer crew was able to pile three large dump-truck loads of the invasive plant to be hauled for composting at 7 Mile Landfill.
The society, now in its fourth year in Port McNeill, needed a project to fulfill its environmental action requirement before provincial judges descend on the town in July to grade its activities.
With the broom taking over the vacant hillside between Pioneer Hill Drive and Campbell Way — the main road linking the town to Highway 19, they did not have far to look.
“That’s been neglected,” Barratt said of the proliferation of broom on the hill, which was cleared of alders four years ago when the Town hoped to make it more attractive to potential developers. “We’ve had a few volunteers from various groups who have tried to address it, but it’s a very big problem.”
The plant was introduced to southern Vancouver Island about a century ago, and quickly began spreading northward. It can be found in large volumes along Highway 19 between Courtenay and Campbell River and recently expanded its territory to Port McNeill, both on the hill in town and along the highway just north of the Campbell Way intersection, where a water line was installed several years ago.
“They exchanged the alder for the broom,” DesRochers said of the lot-clearing that led to the invasion in town. “How it gets from the South to the North Island is primarily human. Wherever there’s soil disturbance, it’ll take hold. Anywhere they’re putting in hydro lines or working on rights-of-way, you’ll see it spring up.”
As a forester, DesRochers is concerned about the possible long-term problems the broom and other invasive species like Japanese knotweed and Himalayan knotweed pose to the North Island’s forests and streams.
“The broom likes sun, but it’s somewhat shade-tolerant,” he said. “It’s a bit of a concern in areas where we’ve harvested and replanted small trees. We’re hoping our young trees can grow fast enough to overtop them.”
The worst way to remove broom, DesRochers said, is to pull the plant’s roots, since that creates the very soil disturbance that allows it to thrive and spread. Barratt’s volunteer crew used hand pruners, hand saws and one power saw to cut the plants just above the ground and below the lowest side shoot or branch.
Barratt said the crew consisted of 12 volunteers, and following its work day a substantial stand of the plants remained undisturbed.
“The number of volunteers we got was more than I expected but fewer than I hoped for,” said Barratt.