Native plants return San Francisco's Presidio

April 22, 2010 7:49:02 PM PDT
Volunteers at San Francisco's Presidio used Earth Day to make room for native plants.

They took out non-native weeds, making more room for species that thrived in the area more than 100 years ago.

A scientist at the Presidio Trust says it is interesting to note that many of California's native grasslands have been pushed out by invasive species.