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January 2007
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March 2007

I've been weeding a lot lately

This is the season when our gardens often look like the weeds are winning. In our mediterranean climate, winter rains bring weeds, many of them natives of The Mediterranean (the European or African lands that border the Mediterranean sea) so they are used to this winter rain-enabled life cycle.

While it is tempting to think of weeds en masse, there are a number of reasons to identify them. The skillful gardener notices new weeds and learns how to fight them before they get a root-hold, and knows which of the usual cast of weed characters have underground structures (like bulbs or running roots) that must be removed if one is to get rid of them.

Identifying weeds can be difficult, but if you can get as far as common name, you can learn quite a bit about your weeds on the following two web sites designed for California gardeners. And, knowledge, as they say, is power.

Find weeds by common or scientific names, read about them or see photos. Look at the national weed list & at the California weed list. Check out the pdf of the Noxious Times, the California Dept. of Food and Agriculture weed management newsletter.

This site offers a weed photo gallery that is searchable by common name. From here you can also go to the same weed list searchable by scientific name or by plant family name. You can also read about weeds that cause problems in turf.

Oxalis Attacks Bay Area

I've been getting a number of letters about Cape oxalis (Oxalis pes-caprae), a weed that is now in full bloom in San Francisco. Also known as Bermuda buttercup, this South African native wildflower is has pretty yellow flowers that are cheery to see blooming on weedy road verges, but in a garden, it is a terrible pest. It grows in fall, blooms about now, and then dies back in later spring.

Cape oxalis grows from small tear-drop shaped bulbs that are dormant in summer, so many an unsuspecting gardener has planted in summer without realizing it was there. When it does appear, some think it is a clover, since it has trefoil leaves like a clover, and hope it will add nitrogen to soil. It won't. I have written my February 21st S.F. Chronicle column on this weed and how to (attempt to) get rid of it, so check out on that day.

Oxalis gets its sour flavor from oxalic acid, a substance that is also found in French sorrel, and, to a lesser extent in chard, beet greens, and spinach. We shouldn't eat great quantities of a plant that contains as much oxalic acid as Oxalis, but it is a nice nibble or could be added to salad in small amounts. In fact, I just read an article by a Greek writer about using Cape oxalis with French sorrel and other wild greens in soup or savory pie. I shall try to get recipes!

Some links about seeds

As promised, here are some links about various seed topics. I am putting them up for my class, but they are generally useful. I brought these sites together to help you understand some of the terms you see in seed catalogs, like treated seed, organic seed, and the "safe seed pledge."

Various governmental and NGO websites on different seed topics: (Facts from the US Department of Agriculture about naming and labeling varieties of seed) This explains what is entailed in giving a plant variety, or   cultivar, a name and selling it under that name. (Requirements under The Federal Seed Act for labeling   treated seed) (Interview with Chip Sundstrom of the California Crop Improvement Association about organic certification of seed) (Site of the California Certified Organic Farmers, includes information on organic farming in California and links to the federal organics law) (Pesticide Action Network North America resources on issues related to genetic engineering that include many PANNA fact sheets and many links to other resources.) (A list of seed companies that subscribe to the Safe Seed Pledge, with links to them) The Safe Seed Pledge says that the company won't knowingly sell bioengineered seeds. (A history of the Vavilov Institute of Plant Industry, which was the world’s first seedbank, and an explanation of Vavilov’s “centers of origin” of cultivated crops. This page includes links to related websites and some of the links within this site (to other sites) are broken, but there is enough of interest on the site itself to be worth looking.

Behind the Scenes

Haven't written in this blog so much recently, but much is happening behind the scenes. I am working on a web site, which will link to this blog. I am also shooting digital images, soon to appear here.

I have also begun to teach one of my 3 6-week vegetable and herb gardening classes at City College of San Francisco, and plan to put some links in this blog to sites that offer information on subjects I teach in the class. These include obtaining seeds, seed starting, and saving seeds. Look for these to start appearing in the next week.

I continue to write a weekly Q&A column for the Wednesday Home Section of the SF Chronicle. I also wrote an article on our weedy but edible wild onion which appeared on January 20th in the Chronicle. You can read the column and the wild onion article at

Since I wrote about Allium triquetrum, the Chronicle received 3 letters scolding them for running it, since the plant is a weed. In fact I said it's a weed, and gave a lot of tips for keeping it from spreading or for getting rid of it. I have been able to keep it in a small corner of my garden using these methods, plus I grow some in a planter box. Weed or no, it sure is good to have it growing in my shady garden in the winter. In Golden Gate Gardening, several recipes specify green onion, or wild onion, or garlic chives (Alliium tuberosum), whichever you have at the time.

If you just got my blog address at one of several talks I gave recently, scroll down a bit and see some older entries, and expect a return to more regular ones now.