Home & Garden Columns

For a couple of decades at least, Joe and I have lurked around a few of the little stands of the weed Nicotiana glauca, tree tobacco, that are scattered along Del Puerto Canyon Road just east of I5. Short lurks are part of our usual spring day-trip itinerary along that route from Del Puerto Canyon to Mines Road because we might see Costa’s hummingbirds feeding on the tall shrubs’ tubular yellow flowers, and who knows what other hummers might show up while they’re migrating?  

So it was almost a reflex that made me pull over when I found a streetside stand of tree tobacco in west Berkeley. I’m lucky there wasn’t a lot of traffic there with me. Birders’ reflexes aren’t always adaptive; I remember a fender-bender occasioned by a kestrel who was doing an apparently convincing stage impression of a peregrine at close range over a freeway traffic jam. Having learned from that example, I do try to behave myself.  

Free advice, though: Never tailgate a birder. 

Nicotiana species—there are 45 to 100 of them, depending on who’s classifying—are native to the Americas. Those sweetly night-scented garden flowers are close kin to smoking-type tobacco, currently a favorite political red herring in public places. (Why, no; I don’t smoke it and never have. See? Behaving myself again! That might itself be a bad habit.) 

Come to think of it, I’ve never been on Del Puerto Canyon Road after dark; I’ll have to hie me down to Fourth Street tonight and have a sniff. 

This one is, fide the botanist Howard McMinn, the only woody species that shows up in the United States. Most of the various tobaccos cultivated by the First Peoples are herbaceous. Tree tobacco is native to Argentina, and came here with the Spanish missionaries. 

Tobacco is closely enough related to tomatoes to share some diseases like the dread tobacco mosaic virus, which is why nurseries ask people not to smoke while shopping, even outdoors. If you’re growing tomatoes, you might have been advised to wash your hands after smoking before messing about with your plants.  

It’s no surprise to those who’ve dealt with certain diseases in humans, Ebola fever for example, that one’s closest biological relatives harbor one’s worst epidemiological dangers. We share more diseases with our dogs and cats than with our turtles and snakes, who might harbor salmonella and such but ordinarily don’t suffer from them, and fewer still with our commensal arachnids or the average earthworm.  

The species are in the solanum family, along with potatoes and eggplants and chili peppers (sweet peppers too) and nightshades and Jimsonweed. We have a handsome native California plant, almost a shrub, called blue witch or Solanum umbelliferum, last time I looked.  

Why “witch”? Undoubtedly because of the plant’s association with other solanums and relatives like Atropa belladonna with highly active poisonous and intoxicating compounds. Both A. belladonna and Solanum nigrum get called “deadly nightshade.” Lots of members of the family are toxic or, even when edible, have toxic parts; don’t nibble on tomato or potato greens.  

People do all sports of foolish things with solanums. Smoking tobacco in the mass-produced, everyday, uncritical fashion that’s spread around the world is certainly one of them. People have smoked Jimsonweed for its hallucinogenic qualities, a dangerous idea because one has no way of knowing how concentrated the intoxicating toxins are in a given plant and what dose one’s taking.  

Belladonna is so called because women used it, way back when, as eyedrops to dilate their pupils, one of those “I’m interested” sexual signals that get rotated through the assembly line of fashion.  

Belladonna does have medical uses: you might get a (very low, carefully controlled) dose of atropine extracted from it before surgery to dry out mucous membranes and make the surgeon’s work a bit simpler. Rarely, it’s also used by opthamologists to dilate pupils during an eye exam.  

If you manage to get poisoned by certain insecticides you’ll get dosed with atropine in the ER. My great-auntly advice is to avoid messing with either of them if you can help it.  

Other insecticides are being produced from nicotine compounds. That flea-control stuff that gets applied to the back of the dog’s or cat’s neck is a nicotine derivative, which has the merit of being less toxic to most non-arthropods like you and me and the furry pets than the stuff that older treatments used. I believe the same corporations are making insecticides for plants out of nicotine analogues, too. Seems to me we’re coming full circle and you might want to go smoke a cigar in your garden after all.  

Photograph: Ron Sullivan. 

Glaucous leaves and yellow flowers of tree tobacco. 

Ron Sullivan’s “Green Neighbors” column appears every other Tuesday. Her “Garden Variety” column appears every Friday in the Planet’s East Bay Home & Real Estate section.