The National Park Service has started herbicide treatments to control invasive plants along the banks of the Colorado River in the Grand Canyon.

The treatments will run through April 30 and are targeted at non-native plants such as Russian knapweed, camelthorn, pampas grass and perennial pepperweed.

An environmental assessment for the park's exotic plant management determined chemical pest control woud be better than not taking action, and would have no significant negative impact on the park's natural ecology.

The Park Service said the herbicide is approved for water use, but will not be applied directly to the water. It will mainly be targeted to a cut in the invasive plant's main stem to remove the plant without impacting nearby areas.