In my SF Chronicle Column for November, I reported on a weed that has been sighted in San Francisco. It's a native in the Eastern part of the U.S., so I was surprised to find it here, but there it is. I also saw one down the Peninsula this summer, though I forget just where.
The plant is large, 4-10 feet tall, and most parts and stages of it are toxic to most mammals. I described it in my column, but was unable to get a photo of it into the print version. However, I can show a photo here. This is an image of a stem of berries. Botanists call this kind of flower or fruit-bearing stem a raceme. The berries are dark purple. When they are ripe, their stems and the longer central stem of the raceme are usually bright pink. The stems of ripe berries are the most recognizable parts of the plant.
Photo by Andra Sadoun
You may find it surprising, given the toxicity of this plant, to know that it has long been a part of the diet of rural people in the South and eastern-central parts of the U.S.one of the young greens gathered and eaten in spring. Only the leaves of very young plants are eaten, and they must be boiled two or three times, with the boiling water drained off of them between boilings and after the last one. This dish is called "poke sallet." (It important to know that the word "sallet" derives from an old English word that meant cooked greens, not salad, as the raw leaves would be toxic.)
The berries are toxic, and eating only a few has killed small children. Though some say the seeds are the most toxic part, it hardly seems worth the risk to try them. Birds seem immune to the berry toxin, so the fruit is eaten by many kinds of birds, including Northern mockingbird, mourning doves, and cedar waxwings. Raccoons and possums may also be able to eat the berries, though most mammals cannot.
The most toxic part of all is the root. The plant is perennial, likely to regrow from last year's roots, so the best way to get rid of it is to dig it out. Wear gloves, as the toxin can enter through skin. Then pick up any fallen berries you see, and watch for seedlings. (The young plants are sort of nondescript, with large oval, pointed leaves.)
How did the weed get here? Presumably from bird-planted seed, but it's possible the seed was assisted by some other form of transportation. It could have stowed away in tire treads or shoe treads. While there are domestic varieties, are grown as ornamentals, their leaves look different from the wild plant. (The ornamental varieties are ‘Silberstein’, which has pale, cream-colored leaves with green spots, and ‘Sunny Side Up’, with yellow-green leaves.) The ones being found in the Bay Area seem to have normally green leaves, meaning are not escaped ornamentals.