Students, Justin, Alvin, Robyn, Jayvon, & Jullian,along with their instructor Mr. B and education assistants, Karla & Amy from La Cheim School came to the garden to volunteer and help us with the creek project. We worked very hard all day eradicating and chopping down the invasive blackberries and ivy that have covered the upper part of Cerrito Creek.
For the past 2 years visitors to Blake Garden have been observing an ongoing effort to curtail and eradicate the pampasgrass in the "Australian Hollow" section of the garden. Originally from South America, Pampasgrass -- Cortaderia selloana -- was introduced into Blake Garden by Anita Blake & Mabel Symmes in the 1940’s (possibly even earlier). On her notecard Mable dates the addition of Cortaderia selloana as 10/31/41 and gives it collection number 602. Archival Photographs from 1958 show the pampasgrass thriving in Australian Hollow. Since it’s introduction in the garden over 65 years ago, the pampasgrass spread out and down into the marshy area of Australian Hollow. No doubt valued as an exotic -- and beautiful -- plant by collectors such as the Anita Blake, pampasgrass is now considered an invasive species, and can be a particularly troublesome weed in the Bay Area. Current eradication efforts in the garden have been concentrating on the area indicated by the oval in the above montage. The process is difficult and the project is long term, but progress is being made with the help of UC Students and garden volunteers. For more information about pamasgrass and invasive species in general visit the: UC Weed Research & Information Center.
Students from Professor William Berry's ES 125 class, Environments of the San Francisco Bay Area, have been volunteering in the garden for the past few weeks to work on the creek project. We have been clearing the invasive blackberries and Algerian ivy and other invasive species from the creek area to study the creek channel, and uncovering and assessing an earlier bank renovation. As we are clearing we have been mulching the area to slow the regrowth of weeds and to add organic matter to the very heavy clay soil. We have also been removing years of trash and debris that has washed in and blocked the flow of the creek.
Elisabeth Esterer-Vogel, a second year Landscape Architecture graduate student in the UC Berkeley Landscape Architecture Department is working on a special LA 299 project. She is investigating methods of perma-culture & education in public gardens. She has recently been working on reclaiming an area of the cottage garden that had been overtaken by invasive Himalayan blackberries and replaced them with three species of cultivated, edible blackberries. The cultivars are Navajo, Ollalie berry, and Boysenberry. She first had to eradicate the invasive blackberries, double dig the clay soil area and amend the soil with compost that we are making on the site.
The creek restoration project began about a year ago when we started removing Himalayan Blackberry bushes and Algerian Ivy from the creek bed and trees. The creek is an upper part of Cerrito Creek and is fed mostly by urban runoff when it rains. The creek fills at an alarming rate (see time lapse video). We wanted to see where this water was coming from, and assess the condition of the creek bed and creek bank. We soon uncovered a rotting bridge, an older restoration project done in the 1970's with retaining walls made of concrete bags, some pools that had been made, lots of chatter was strewn in the creek bed, some undercutting and erosion.
[nggallery id=12] PHD candidate Kristen Podolak and MLA candidate Jessica Ludy surveyed the creek that had been opened up by staff and volunteers to start to create a new plan for restoration. (download Kristen & Jessica's paper)
[nggallery id=11] Later Nathanial Behrends, Master of Landscape Architecture Candidate, from LA 227 Restoration of Rivers and Streams, after reviewing Kristin's work and evaluating the condition of the newly uncovered upper area recommended a series stepped pools for the creek to slow the water coming through the channel to decrease the cutting of the banks. (download Nathanial's paper)
[nggallery id=15] After more removal of berries on the upper part we then discovered the creek was blocked with silt and urban debris that was diverting it from the original channel and creating scouring and cuts in the upper part of the garden. We removed the debris and restored the water to the original channel. [nggallery id=13] A group called The Weed Warriors led by Susan Schwartz of Friends of Five Creeks came in recently to eradicate some of the blackberries. (view time lapse video of The Weed Warriors at work) As we clear more weeds from the creek new opportunities emerge.