When I was growing up, my dad used to have me pull out crab grass from our lawn, because it was – a weed. Well lately, weeds are generating a new respect from scientists. And in a moment, we’ll find out why. I’m Jim Metzner, and this is the Pulse of the Planet. What’s a weed? We asked Rick Stepp, an assistant professor at the University of Florida in Gainesville.
“There’s a lot of different ways to look at weeds and it’s really more a set of characteristics in order to define what a weed is. Generally it’s a plant that grows in an area that has a lot of disturbance caused by humans. Plants that are fast growing that reproduce really quick and they just thrive in areas where other plants wouldn’t.”
Rick studies plants which have medicinal value. And it turns out a lot of them can be classified as “weeds”.
“There’s about 101 plant species that are used for pharmaceuticals. Of those about one third that are pharmaceuticals actually come from weeds. Well if you look at the total world’s flora only about 3 percent of all plant species are considered weeds. So the fact that one third of all plants that are used for pharmaceuticals are weeds means it’s about an order of magnitude higher then what we’d expect.”
“Weeds generally have negative connotations because they’re growing in areas where people don’t want them to be and because they do grow relatively fast and invade where other plants are trying to grow. People don’t like to see them in yards and gardens and areas like that. However, a lot of these plants for the very reason that they’re so fast and thrive in disturbed areas are the same reasons that they have bioactive compounds that might be useful as medicinals.”
Well if only I had known about this when I was a kid, maybe I wouldn’t have had to pull out all that crabgrass. We’ll hear more about medicinal weeds in future programs. Pulse of the Planet is presented by the National Science Foundation . I’m Jim Metzner.