Q: I’d like to grow some goji berries. Will they make fruit in San Francisco?
A: Goji berry, also known as wolf berry, is the latest miracle food craze. If ads are to be believed, among its many benefits are cancer prevention, healthier heart and arteries, and treatment for diabetes and obesity. Is any of this true or is this a skillful effort to part you from your hard-earned cash? I’m not an expert in herbal pharmacology, but generally have a healthy skepticism of such varied claims for a single food or herb. And I have learned that, although the berries have long held a place in Chinese medicine, many claims for them are quite recent and not yet subjected to well-designed clinical trials.
As far as I can tell, this is an edible fruit with a good vitamin and mineral content and some interesting phytochemicals that may promote health. It is usually sold dried, looking like a rather narrow red raisin. In the interest of research, I bought a few to taste – at $20 a pound! I found them to be quite sweet with a touch of acid.
To find out whether the plant can be grown and produce berries here, we need first to identify it. A little research reveals that it is in the same plant family as tomatoes and potatoes. The two species grown for the berries are Lycium barbarum, originally from the Mediterranean region, and L. chinense, from China or Tibet. Both are now widely distributed, including as weeds in nearly every state. The bright red berries are produced on shrubs up to 8 feet tall with small narrow leaves, purple flowers and sometimes a few thorns.
I’ve never seen either plant growing as a weed in San Francisco, and thought I’d never seen them at all. But when I learned that another common name is matrimony vine, I realized that this is the plant I’ve noticed growing in community garden plots of Chinese Americans in San Francisco. The plants are cut frequently to use their leaves in soup. I’ve never seen flowers and fruit on them, but whether this is because they are cut back so often, or not adapted to the climate, I have never known.
I did locate directions for growing L. barbarum. Sources all emphasize how easy it is. It needs little fertilizer, and little water once established, tolerates cold to minus-10 degrees Fahrenheit and high summer temperatures. Yes, I thought, but does it set fruit when summers are cold, or does it pout, like a tomato? Does it require a colder winter to bear fruit? No answers.
The closest I came to answering these questions was that L. barbarum is listed in the 2001 (but not the 2007) edition of the Sunset Western Garden Book. It says L. barbarum will do well in Sunset’s zone 14, which includes Santa Rosa, Sonoma, San Ramon and similar inland locations, but does not suggest growing the plant in the cooler summer zones 17 (San Francisco), 16 or 15. So I’m doubtful L. barbarum will produce fruit near the coast.
However, if you want to experiment, you can get L. barbarum plants from Garden Harvest Supply (gardenharvestsupply.com, (888) 907-4769) or from One Green World (onegreenworld.com, (877) 353-4028). If all goes well, the plants bear in two to three years, producing about a quart of fruit per plant. If you don’t get fruit, you can always make soup from the leaves. But watch out for tomato hornworms, a pest goji berry plants share with that other tasty and healthful fruit we struggle to grow.
Q: Help! Something (not birds) is eating my snap peas just as they are emerging. Nothing is visible on the surface. Could there be a pest in the soil?
A: In our region, winter pea seedlings are a favorite food of hungry slugs, which hide in crevices or soil and come out to eat at night. A few careful searches with a flashlight at 10 p.m. or later will let you see and dispatch many of them.
I usually protect winter-sown peas with a floating row cover, a translucent polyester cover sold for gardens. I cut a strip a foot or so longer than the row and 1 1/2 to 2 feet wide and make a bubble over the row, tucking the edges firmly into the soil. I take it off when the plants begin to push against it and guide the plants toward the trellis I set up at planting time.