LAKEPORT– Lake County has hundreds of invasive weeds. That fact was stressed during the annual Invasive Weed Tour on Thursday.
The tour was part of California”s Invasive Weed Awareness Week. The tour was sponsored by the Lake County Department of Agriculture, Lake County Department of Water Resources and Upper Lake Watershed Coordinator Greg Dills.
Approximately a dozen people participated in the tour that included stops throughout the county where various invasive plants were viewed and how steps are being taken to either control or eliminate them.
The top 10 invasive plants in Lake County are artichoke thistle, Tree of Heaven, Spanish bloom, tamarisk, Arundo, Scotch broom, French broom, black walnut, bamboo and bull thistle.
According to Dills, two of the more numerous foreign plants are Arundo and Tamarisk. Arundo is a giant reed and originally came from India but is now common in Lake County. It first appeared in America in the early 1800s where it was planted as an ornamental plant and also to stop erosion along canal banks. The problem is that its roots can cause extensive damage and it will also crowd out other desirable plants. It has no natural enemies in North America and in India the primary predators of the plant are elephants.
Tamarisk is another invasive plant that is found throughout Lake County. Dills said that Tamarisk presents a huge fire danger, especially when it is located near homes. The plant came from China and is another ornamental plant.
According to Dills, the plant can use up to 300 gallons of water per day and is very hard to control.
Carolyn Ruttan of Lake County Water Resources Department explained how various invasive aquatic plants impact the lake. She said that water primrose is abundant on the lake and spreading. It can be identified by its green leaves and bright yellow flowers. The plant can choke up channels and make boating nearly impossible. It also crowds out the native tule plants. Primrose can be controlled by spraying it a herbicide and cutting it. However, the operation is very expensive. Other aquatic weeds that present a problem are sago pond weed, curly leaf pond weed and hydrilla. She said that Clear Lake, with its abundance of nutrients, create ideal conditions for aquatic weeds to grow. The county controls these weeds either by spraying them with an herbicide or by mechanical harvesting.
This summer algae is foremost on the minds of Clear Lake boaters and other recreational users. Algae are tiny water plants that cycle normally between the bottom and the surface, floating up and sinking down. Ruttan said there are 130 different species of algae in the lake. The most common are Lyngbya and Gloetrichia. Lyngbya is a filamentous algae and has been in the lake during its entire three million year existence. Ruttan said the Gleotrichia algae is the golden-brown algae that has recently bloomed around the lake.
Dills told the group that grant funding has paid for most of the eradication of invasive plants but that funding is drying up as budget cutbacks have an impact on all programs.
He said that because of the importance of controlling invasive weeds in the county that he is always looking for new sources of funds.
Tour participant Brockman Kreiss of Clearlake Oaks, and a member of the Lake County Grand Jury, summed up the attitude of the other members of the tour group when he said he never would have thought there were so many different species of foreign plants in the county. He said the tour was extremely informational.
