“Plants smell,” says botanist David Chamovitz. Yes, they give off odors, but that’s not what Chamovitz means. He means plants can smell other plants. “Plants know when their fruit is ripe, when their [plant] neighbor has been cut by a gardener’s shears, or when their neighbor is being eaten by a ravenous bug; they smell it,” he writes in his new book, What a Plant Knows. They don’t have noses or a nervous system, but they still have an olfactory sense, and they can differentiate. He says there’s a vine that can smell the difference between a tomato and a stalk of wheat. It will choose one over the other, based on…smell! In a moment I’ll show you how.
This talented plant is commonly known as the dodder vine. It’s a parasite; tomato gardeners know it and hate it.
Here it is at Penn State University — look for the stringy, wiggly thing on the left — sniffing. Notice as it grows from a seedling, it moves in small, lazy circles, like hands groping in the dark, and then, gradually, it leans toward the stalk of the tomato plant — which it then entwines, gouges, sucks and strangles