One of the sites we work at regularly is Mt. Burdell, a Marin County Open Space Preserve. Located at the northern edge of Novato, Mt. Burdell has serpentine grasslands with rare plants, an incredible array of oaks, and seasonal streams that support milkweed – the critical host plant for Monarch butterflies. Marin CNPS started working at Mt. Burdell because a member who regularly hikes here noticed invasive plant species moving into grassland habitat. They wanted to protect this important and beautiful place, and reached out to Marin County staff to see how they could help. Marin County Open Space District (OSD) staff were receptive to working together and co-hosting volunteer events. With strong support and leadership from Marin County OSD, we began partnering on stewardship programs in 2025.
Our work at Mt. Burdell has focused on removing yellow star thistle (Centaurea solstitialis) from the grassland and Himalayan blackberry (Rubus armeniacus ) and pennyroyal (Mentha pulegium) from riparian corridors, as well as controlling a large patch of Bermuda buttercup (Oxalis pes-caprae) near a preserve entrance. In addition, we have worked with Marin County OSD nursery staff to plant narrow-leaf milkweed (Asclepias fascicularis) to bolster the small existing milkweed population. Monitors have found Monarch caterpillars on this milkweed!