“It grows in dense thickets that block sunlight and out-compete native specialty plant species, many of which are listed as endangered,” said Jen Michelsen, the water district’s environmental programs manager. “However, removing mature French broom in the sandhills habitat is challenging because of its huge root systems.” The water district manages roughly 2,000 acres of land in the San Lorenzo Valley Watershed. Of that land, 180 acres is sandhills habitat within the Olympia Watershed — an area in the Zayante area northeast of Felton. The sandhills are basically the exposed remnants of an ancient seabed. In 1963, the fossil remains...