Bidens biternata. Image: Wikipedia.
Judging by the cries of dismay in the comment section on yesterday’s post, I believe it is time for a small correction of official Root Simple opinion on the weed Bidens. I didn’t get to see yesterday’s post before it went up and if I had, I probably would have added a paragraph praising Bidens, despite its wicked little seeds. Erik was frustrated when he wrote that post because he had just spent an hour pricking the hitchhikers out of his clothes. I don’t blame him, because the same thing happened to me when I pulled some the week before, and cleanup wasn’t fun. They weren’t only in my clothes–they were buried in my skin! Getting them out of dog fur must be a real joy. This is a mighty persistent weed.
But it is also a popular one. This summer has been an education in Bidens for me–though I did not know its name for a long while.
It was a weed I’d never seen before, which is odd, because I feel like I know my local weeds. This one is exotic to me. It spontaneously erupted in our front and back yards around midsummer. (Was it in the mulch? Carried on a wandering cat or possum or goldfinch?) I was intrigued by its delicate leaves, which appear very genteel and vaguely floral. I was curious as to what kind of plant it was–so I let it be. Eventually it developed small unspectacular yellow flowers. In my mind it was a pretty-ish weed, unidentified, but fairly harmless. I kept meaning to look it up, and at the same time, I pondered pulling it because it was competing for water with my more officially invited garden plants. (Since then I’ve learned that it might give off competitive chemicals, so probably isn’t the best companion to plants I actually want to keep in my garden.)
I am always curious about volunteers in the garden because they’re saying something about the state of the garden. In permacultural terms, the soil calls the weeds it wants and needs. I’m not smart enough to know what the Bidens signifies yet, but I’m keeping my eyes open.
What I could see, though, easily, was the busy cloud of insects buzzing around this mystery plant: honeybees, little native bees and flies and these tiny orange-ish moths that I’ve never seen before. Good pollinator plants remind me of space stations (the kind in movies, that is): complex structures full of vehicles of different sizes approaching, docking, departing, filling the airspace with frantic activity all the day long.This was definitely a good pollinator plant, an important source of nectar in a dry season, so I left all the plants in place.
My only regret came when the blooms were mostly gone and it was time for fall clean-up in the yard. I pulled it. That’s when I discovered that Bidens bite! Those seed clusters, which are beautiful black starbursts on the plants are murder to the unsuspecting gardener. I did warn Erik! I may have failed to tell him about its pollinator feeding qualities–but I definitely told him to be very careful if he pulled any. He just didn’t get how careful!
Only after our encounter with the seed did we finally get serious about ID-ing the plant. As Erik mentions in his post, the Facebook group Plant Identification told us it was some type of Bidens, and after further poking around I’m going to tentatively identify it as Bidens biternata.
Finally, as our commenters noted, it is a medicinal plant (And, as another reader pointed out, Bidens aurea makes a natural red/pink/orange dye). I can’t comment much on it’s medicinal value, because I haven’t done much reading about it yet, but what very little I’ve read already has me wanting to tincture some of it for its antibacterial properties. Unfortunately we’ve just pulled all of it from our yard and sent the plants away in the green bin, but little baby Bidens are popping up already, so I think I’ll let a few of those grow out. I have the feeling that Bidens is going to be a new permanent resident in our yard.
Beware the 
