The City of Mountlake Terrace has not been immune to the influx of non-native plants now present in the Puget Sound region. At least 10 species of non-native invasive plants have been observed in the city. There are 3 species where control efforts are currently focused within our parks and rights-of-way:
Herb Robert is found under the over story of native trees. It out competes other native ground cover and can form a dense mat on the forest floor. It is rapidly spreading throughout Western Washington.
Japanese knotweed is an escaped ornamental that is becoming increasingly common along stream corridors and rights-of-way in Washington. The species forms dense stands that crowd out all other vegetation, degrading native plant and animal habitat.
Nightshade has an aggressive root system that can grow deep into the ground and give it a competitive advantage over other ground cover and small shrubs. Nightshade also contains substances within the roots, stems, leaves and berries that can be toxic to humans.
The City has worked with volunteers and has provided resources to help control these plants along stream corridors and within City parks.
Fragrant Water Lily
Invasive Fragrant Water Lily Vs. Native Yellow Pond Lily
On Lake Ballinger, Fragrant Water Lily has taken hold in many areas around the shore. Fragrant Water Lily is not native to Washington State but has been imported for use as an ornamental in backyard ponds and is now found in many of the shallow lakes in the area. It has overtaken native Yellow Pond Lily in many areas around the lake.