Lime Ridge Open Space provides a 1,700-acre buffer between Walnut Creek and Concord. Though surrounded by suburbia, it's part of an important arc of preserved land extending nearly from downtown Concord to Mount Diablo State Park. And it still holds some secrets, including two just recently recognized species of wildflowers, the Lime Ridge navarretia and Lime Ridge woollystar. And it is one of few places legendary Mount Diablo botanist Mary Bowerman found the recently rediscovered Mount Diablo buckwheat.
Any springtime hike here rewards us with an unusually wide array of flora. While nonnative grasses have taken over many areas, look for wildflowers such as woolly paintbrush, Mount Diablo sunflower, and Brewer's groundsel along trails, rock outcroppings, and the borders of chaparral.
Lime Ridge has some scars as well: From 1905 until 1946, travertine limestone was extensively quarried here. A nearby smokestack was torn down in 2009, but a fenced-off cell phone tower still looms on the ridge. Save Mount Diablo and Walnut Creek Open Space Foundation have been negotiating limits to further development of the site and have advocated removal of the antennae.
Getting there: There is parking and a trailhead at the corner of Ygnacio Valley Road and Cowell/Montecito. From there, you have a choice of several trails and fire roads.