Lake County, CA Invasive Plant Rules: Prohibited Species (2026)

Chapter 26A of the Lake County Code identifies nine non-native, invasive aquatic plants of concern under Sec. 15: Hydrilla (Hydrilla verticillata), Spatter Dock or Yellow Pondlily (Nuphar polysepala), Water Hyacinth (Eichornia crassipes), Purple Loosestrife (Lythrum salicaria), Giant Salvinia (Salvinia molesta), Eurasian watermilfoil (Myriophyllum spicatum), South American Spongeplant/Frogbit (Limnobium laevigatum), Parrotfeather (Myriophyllum aquaticum), and Brazilian waterweed (Egeria densa). Sec. 26A-4 extends the ban to any part of these plants capable of propagation. Under Sec. 4. The Board of Supervisors adopted the ordinance (Ord. No. 2774, 6-6-2006) after finding that these species spread rapidly and eliminate native flora and fauna, most notably in Clear Lake, declaring them public nuisances under Government Code Section 25824.

A grower or nursery believing a particular variety or cultivar of a listed species is actually non-invasive can petition the Agricultural Commissioner for an exemption under Sec. 26A-6 using the Commissioner's 'Petition For Exemption' form; the Commissioner must decide within 45 days of a complete submission (30 days after any additional requested information is received), and an unfavorable decision can be challenged once more with new supporting data. Enforcement runs through the Commissioner's office under Sec. 26A-7: any plant found in violation is placed under a hold order barring further movement without the Commissioner's consent, and the responsible person must ship the plant out of Lake County within 48 hours or destroy it at their own expense, with the Commissioner present to witness release or destruction.