SF Bay Sea Lavender Control

Limonium

Cal-IPC and partners prioritized Algerian sea lavender (Limonium ramossisimum) and European sea lavender (L. durisculum) as top priorities for removal to protect San Francisco Bay tidal marshes. These plants are found in several other locations along the California coast (for instance, Morro Bay, Carpenteria Marsh near Santa Barbara, and San Diego), and are a prime candidate for early eradication before they spread further. California’s salt marsh habitat is home to a unique assemblage of plants and wildlife, and much of this habitat has been lost to development. Few weed species can thrive in this habitat, but sea lavender is spreading aggressively so it is critical that we address it before it becomes too widespread to control. The effort in San Francisco Bay is aimed at full eradication if possible. However, each sea lavender plant can put out thousands of seeds that float, so we will have to gauge effectiveness as removal efforts progress. There are some fifty known locations around the Bay, many of them small. After our first two years, we have brought a dozen of the largest sites under management, representing 50% of the infestation by area. In years 3 and 4 we plan to expand our reach to bring 90% of the area under management.

 

 

Plants being managed

Start date

2016

Location

San Francisco Bay tidal marshes Project map in Calflora Central Coast region

Resources protected

Tidal marsh habitat supporting endangered wildlife (Ridgeway’s rail, salt marsh harvest mouse), sensitive plants (salt marsh bird’s beak), and migratory waterfowl.

Project goal

Cal-IPC and partners are aiming for full eradication of invasive sea lavender from San Francisco Bay. This will likely take a decade or longer. Though the total area infested is only 16 net acres, this is spread out over 55 sites around the bay, and each plant can produce thousands of seeds. To date, control has been started on half of all non-native Limonium in the bay.

Project photos

Limonium
Removing sea lavender by hand in Strawberry Marsh, Marin County. Photo by Drew Kerr.
Limonium
Treating Limonium outliers in San Mateo County on the SF Peninsula. Photo by Drew Kerr.
Limonium
Invasive sea lavender can grow densely in mid-marsh elevations, altering the vegetation community. Photo by Drew Kerr.