Bringing Back Natives at Walnut Creek Open Space

Bringing Back Natives in the Walnut Creek Open Space

If you spot a group of tree-hugger types out in the Walnut Creek Open Space planting acorns or native grasses and wielding hoes, shovels, and weed-whackers, you probably encountered one of the Walnut Creek Open Space Foundation restoration projects.  In this excerpt from the Walnut Creek Open Space Foundation newsletter, Lesley Hunt, Foundation president, reviews our numerous restoration projects and how successful they were—or not. Want to help?  Check out our website at wcosf.org, or go to our Facebook page, Walnut Creek Open Space Foundation.

The Foundation's restoration efforts began in 1990 when Dick Daniel, resident and user of the Open Space, noticed that there were no young oaks in the Open Space, although there were plenty in his back yard.  After some experimentation he, his friend Ralph Kraetsch, and Dan Cather (then Open Space manager, now retired) concluded the problem was cattle grazing.  Cattle were excluded from part of Shell Ridge and the following year the Oak Habitat Restoration Project, sponsored by the Foundation, began under Ralph’s leadership.  Twenty years later, 700 oaks in Shell Ridge, Lime Ridge, Acalanes Ridge, and Sugarloaf survive from the 2500 sites we planted and there are many more volunteer seedlings.  By any measure, this is a success.

After a couple of years Ralph began to experiment with planting native grass at several sites in Shell Ridge.  In 2003 Foundation member Bill Hunt began planting grass in the Heather Farm Nature Area and a couple of years later, Lesley Hunt started another grass project at the Sutherland region of Shell Ridge.  All these projects grew to be quite large but ultimately they failed to hold their own against the weeds.  The most likely reasons are inadequate site preparation and follow up weeding.

In 1996 Ralph turned his attention to mowing invasive weeds with varied success.  One major factor was the nature of the seed banks—seeds built up in the soil over the years--at each site. 

About that time, Foundation volunteer Bob Wisecarver began a project at Borges Ranch in Shell Ridge to provide increased cover and food for the quail who used the area.  This was a resounding success – the quail have increased tenfold.  However, efforts to replicate that success elsewhere haven't gone as well.  We're still experimenting.

The component that all these projects have in common is that they focused on a single habitat element.  (Heather Farm actually included all the elements but the effort on grass overshadowed everything else.)

In 2008 Bob Simmons (then Foundation president) proposed deepening Bayberry Pond in Lime Ridge and restoring the area around it.  This led to our first “all inclusive” project where we worked on all the major elements equally and at the same time (trees, chaparral, grass, flowers, and riparian).  It has been successful.  After his election to the Walnut Creek City Council that fall, Bob moved over to Shell Ridge’s Deer Lake and employed the same approach there in a low-key way.  Foundation member Sean Micallef is now doing the same at Indian Valley Pond in Shell Ridge.

We have also started three new limited-focus projects building in part on what we learned from the earlier ones.  Foundation board member Phil Johnson has led an effort to remove yellow star thistle from the spine of Shell Ridge by doing very thorough weeding.  It is labor intensive but successful.  He, Foundation members David Ogden and Brad Heckman also started a mustard eradication project at Sutherland employing mowing and weeding.  We have just started to plant grass there using methods Lesley Hunt worked out at Bayberry.  Most recently, we applied our knowledge of weed seed banks to removing yellow star thistle below Twin Ponds in Shell Ridge.

The next stage in the evolution of our projects will probably be either to scale them up or increase their species diversity. In anticipation of this, we have started an effort to refine our restoration policies.

Want to help? Your Open Space Foundation welcomes volunteers on any of our projects, regardless of your experience.  If you like working outside in fresh air, enjoy moderate exercise, and want to learn about native plants, we have a place for you. Visit our website, wcosf.org, or our Facebook page.