The idea to profile 30 native plants growing in my yard in September may have been a bit too ambitious. The more realistic number is 10 which I may continue to do each month going forward. My 10th and final plant pick for September is bidens alba (or pilosa), a hearty sun loving plant that really shines in Atlanta starting in September. The common names are numerous and include, stickseed, shepherd's needle, Spanish needle, common beggartick, bur-marigold, tickseed sunflower, pitchfork weed, butterfly needle, cobbler’s pegs, hairy beggartick, black-jack, farmer’s friend, and romerillo. The word bidens means two-toothed which describes the seeds which look like tiny sharp pitchforks. The seed dispersal is zoochorous meaning it is designed to be spread by animals, so the seeds do a great job of sticking to anything that comes near them!
I became intrigued with bidens alba on a family beach vacation when I saw an incredible number and variety of pollinators on a patch of it on a bike ride. Shortly after the vacation we were walking our dogs around our neighborhood, and I saw a random patch of bidens alba at the edge of an otherwise manicured yard. It was also buzzing with life! A couple seed heads from both patches may have followed me home and were added to a handful of bidens alba seeds native plant friends gave me when I started asking around about it.
Bidens alba is considered a valuable habitat plant. It is a butterfly and moth host plant, and in Florida it is the third most reliable source of nectar for pollinators. I won’t try to to give every bit of information about bidens alba here because there is so much already written about it. In addition to the medicinal and edible qualities noted elsewhere, Eat the weeds, a blog focused on foraging, has some of the most interesting information that I could find about bidens alba in one place. Another blogger named Kevin Songer who writes about survival gardening explains why bidens alba is one of the top 10 plants to have.
After I planted it to grow with other plants in a sunny area along a border fence in my front yard, I learned bidens alba has allelopathic qualities, meaning it suppresses the growth or germination of nearby plants in some way. I’m not sure just how allelopathic it is, so I’ll keep an eye on it to see if I need to remove it from this area and let it free range in a more out of the way area. I think a thin strip of land on the side of my backyard fence that my oddly hostile lawyer neighbors won’t let me access because I would need to “trespass” on their property by a foot or so would be the perfect spot for it. I can maximize the pollinator potential in an otherwise dead space and in the process maybe kill a few of the invasives from their yard that creep under the fence into mine!
Each bidens alba plant has up to 6,000 seeds that can remain viable up to five years. It also has an average high germination rate around 80% or higher so you never have just one bidens alba plant! Fortunately, you can easily pull up bidens alba plants where you don’t want them because the roots are not deep. This would be a great guerilla gardening native plant!
Bidens alba is thought to be native to North America and has an almost identical twin bidens pilosa that is considered an introduced species from Central and South America. There are differences such as larger leaves and more flower petals in the bidens alba, but the two can hybridize and have been classified into the same species which only makes identification more complex and confusing for the average person. They are both now grouped as bidens pilosa so I'm going to call mine native bidens alba and let the plant wonks fret over the details.
For my purposes, bidens alba is a perfect throw-the-seeds-and-be-done-with-it native plant for a challenging sunny to partly sunny area where I need a generalist pollinator powerhouse plant from summer through fall.