"Don't water your weeds." – Proverb
LOWER LAKE, Calif. – The Lake County Weed Management Area recently hosted its 14th annual "Invasive Weeds Tour" at Anderson Marsh State Historic Park.
Since July is "California Invasive Weed Awareness Month" an interesting and energetic collection of participants and presenters were present.
The weed walk was sponsored by the Lake County Department of Agriculture and the Lake County Resource Conservation District, or LCRCD, with Charlotte Griswold, president of LCRCD on hand.
This walk was encouraged to educate the public about the increasing amount of non-native invasive weeds that proliferate in our parks, yards and landscapes, and the results of this influx.
After the walk a lunch was provided in the shade of the ancient oaks near the Anderson Ranch House. The event then culminated in a discussion of aquatic invasive plants – another important topic for our diverse county to consider.
Some of the experts who led and discussed the central topics included Trish Ladd, environmental scientist from the California Department of Parks and Recreation, Bill Lincoln of LCRCD, Victoria Brandon who works with the Lake County Land Trust and Sierra Club, Catherine Vanderwall of the California Department of Food and Agriculture, McLaughlin Natural Reserve Director Paul Aigner and Anderson March Interpretive Association Board Member Henry Bornstein. Also in attendance were some of the group from the Lake County Master Gardeners.
Identified on the walk, some of the many invasive plants that are taking over the grasslands at Anderson Marsh State Historic Park and other California regions are curly dock, some kinds of morning glories, Italian rye grass, Himalayan blackberry, vetch, and many more European and Asian grasses.
A familiar invasive plant is the star thistle, a noxious weed that probably arrived in the Bay Area during the Gold Rush era. It originated in Turkey or Greece.
The release of a particular type of weevil, along with control burns and herbicides in some areas, have somewhat reduced the onslaught of starthistle plants.
Lake County enjoys a temperate climate which is conducive to the growth of a variety of plant life. This is true of most of California.
Because of its temperate climate there are around 6,300 native plant species in our state. Both native plants and non-native plants, or invasives thrive, due in part to this temperate climate, but our landscapes and creeks can become ruined by exotic plants who take up nutrients and water in the soil that were intended for the natives. Invasive plants may add fuel for fires, as well.
Once the invasive plants take hold they are also prone to change the habitat and leave the plants and animals who once lived in a niche high and dry.
Although the change to the landscape is small, each minute alteration in the biodiversity breaks an important link in the chain that is important to the environment.
Where do these unwanted plants come from that are crowding out and threatening the landscape?
They sometimes arrive via our gardens or aquariums, sometimes escaping and growing where they are unwanted. They hitchhike on clothing, vehicles or animals, and sometimes through agricultural feed and seed.
The goal is to restore grasslands to the conditions prior to European arrival, and to promote native plants.
With the serpentine soils found in Lake County a refuge of sorts is found to enhance the native grasses, because non-natives do not thrive as well on the serpentine soils.
Where the soil has been intensively disturbed due to farming or other means, the invasive plants begin to take hold, even blotting out the state grass, purple needle.
Various methods to deter non-native plants have included herbicides and professional prescribed burns.
Afterwards native grasses can be planted, including perennial and annual plants for stability to deter re-invasion.
On a smaller scale, hand-pulling or even solarization – when the young plant is covered, thereby “smothering” it before it takes hold, are often effective deterrents to invasive plants.
Kathleen Scavone, M.A., is a retired educator, potter, writer and author of “Anderson Marsh State Historic Park: A Walking History, Prehistory, Flora, and Fauna Tour of a California State Park” and “Native Americans of Lake County.” She also formerly wrote for NASA and JPL as one of their “Solar System Ambassadors.” She was selected “Lake County Teacher of the Year, 1998-99” by the Lake County Office of Education, and chosen as one of 10 state finalists the same year by the California Department of Education.
The Living Landscape: The annual invasive weeds walk
- Kathleen Scavone
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