Above:Rolling up ivy at Mortar Rock.

Below: Hacking acacias out of Grotto Rock.

Mortar and Grotto Rock Parks

Berkeley's Mortar Rock Park is named for the many hollows worn by Native American women pounding acorns and other seeds. The small park, with magnificent bay and buckeye trees, was little used, overrun by ivy that hid broken glass and smelly dog poop. Beginning in 2007, Friends of Five Creeks volunteers rolled up and hacked out the choking ivy, planted natives, and installed an interpretive sign.

At nearby Grotto Rock Park, with magnificent sunset views, volunteers did heavy-duty invasives removal, planted natives, and built safe new trails and steps. Volunteers from UC Berkeley moved 10 tons of decomposed granite in one day to make a new path! Scroll down for a slide show of our work.


  • By car: From Marin Circle, start north on The Arlington and immediately angle right, uphill, on Indian Rock. Pass Indian Rock Park. Mortar Rock Park is on the right, just past the north end of Oxford Street, opposite the south end of San Diego. For Grotto Rock Park, continue up Indian Rock its end at Santa Barbara. Turn left -- the rock is on your right. Or take Santa Barbara north from Spruce or Marin to Grotto Rock Park.
  • By bus: Take AC Transit 67 to Spruce and Marin. Walk down Marin one short block and then turn right, north, onto Santa Barbara. Grotto Rock Park is a few houses north, just past the top of Indian Rock Avenue. Walk down Indian Rock Avenue to Mortar Rock Park. Or take AC Transit 7 or 18 to Marin Circle, then ,follow driving directions, above, on Arlington and then immediately up Indian Rock Avenue.