Weeds Out, Natives In

Rose Creek Watershed Project Limits

Invasive Plants Pose Major Threat

Wasp-infested eucalyptus leaves

Dense human communities can pose a significant threat to the ecological health of nearby natural canyons in the form of escaped, non-native, invasive plants. Some of the worst offenders are ice plant, giant reed, Pampas grass, and eucalyptus trees as they spread rapidly, displace native plants and animals, and increase the risk of fire and flooding in creeks and canyons. Eucalyptus trees have shallow roots and are a threat to public safety when they topple in wind storms. Falling limbs are another public safety threat from eucalyptus trees that have been infested and weakened by a type of wasp. Oil in eucalyptus leaves suppress the growth of native plants and soil bacteria, creating dead zones with few native species.

Pampas grass and ice plant grow in dense patches to the exclusion of any other plants. All of these invasive plants crowd out native plants like oak trees and California sagebrush that would otherwise provide a home for native wildlife like bobcats, gray foxes, barn owls, acorn woodpeckers, and California gnatcatchers.

Invasive Plant Removal Now Underway

Following years of planning led by Ann Van Leer of the Land Conservation Brokerage and San Diego EarthWorks, The Chaparral Lands Conservancy has received grants and donations and secured agency permits to implement the project. Starting in the fall of 2012 and continuing for several years, the Conservancy’s contractor, RECON Environmental will work to eradicate several select invasive plants. Herbicides are an important tool to remove invasive plants and their use has been approved by several agencies. Herbicides are designed for application near streams and are similar to Roundup. RECON employees are specially trained and certified to apply herbicides. A blue or green dye is added to the herbicide to mark treated plants, and treated plants may be retreated in subsequent years or reduced by cutting dead plant materials to the ground. In many cases, native plants will quickly colonize areas where invasive plants have been removed, and the Conservancy is pursuing future projects to replant native plants in treated areas to speed recovery of native habitats.

Public Education as Long-Term Solution

The Rose Creek Watershed Invasive Plant Control Project will be coordinated with a complimentary program to educate watershed residents and nurseries about non-native invasive plant species and the importance of choosing landscaping alternatives. An “adopt your watershed” program will also be conducted to educate nearby residents, businesses, and groups to reduce future invasive plant problems. One exciting element of the project brings together removal of invasive plants and educational outreach at University City High School where RECON will remove a dense stand of stunted eucalyptus trees and students will subsequently replant the area with native oaks, willows, and other plants, water the plantings, and study the results.

You Can Help!

If you live in the watershed you can help by removing any invasive plants from your property. Contact Watershed Coordinator Kelly Makley to see if volunteers are available to help. Check out the Don’t Plant a Pest brochure for native plant landscaping alternatives that are not only beautiful but can also save money with less water and fertilizer. You can also visit the California Invasive Plant Council or PlantRight to learn more about invasive plants.

The Chaparral Lands Conservancy is grateful for supporters who have provided funding and time to make the Rose Creek Watershed Invasive Plant Control Project a success:
Ann Van Leer, Land Conservation Brokerage
Deborah Knight, Friends of Rose Canyon
Julie Fontaine, Trestles Environmental
Mark Carpenter, KTU+A Planning and Landscape Architecture
Kelly Makley, Watershed Coordinator
State of California Wildlife Conservation Board
San Diego EarthWorks

For more information on The Chaparral Lands Conservancy, please contact David Hogan, director.

The late December deluge of 2010 made for a great month of vernal pool searching in January as part of our Proctor Valley Vernal Pool Project. Conservancy Director David Hogan spent days surveying Proctor Valley to confirm past dry season mapping of potential pool areas. This effort has identified dozens of previously undocumented vernal pools and 11 potential intensive pool restoration areas, all of which will be included in a pending, comprehensive Proctor Valley Vernal Pool Management Plan. The beautiful vernal pool shown in the picture at left is a rare bedrock-type pool (most San Diego County vernal pools are formed by sandstone or clay) located on the California Department of Fish and Game’s Rancho Jamul Ecological Reserve and had never before been mapped.