Most Bidens species share the trait of having seeds that stick to anything passing their way. In Latin, bidens refers to having two teeth, in this case the two teeth on the seed. The flowers of many Bidens species have diminutive yellow to white ray flowers, rendering the bloom insignificant for the human observer, but still just as valuable to insects (its the disk flowers that matter). Also these plants produce a lot of seed that can be long lived in the soil. With these caveats in mind let me mention several species that have greater visual appeal and can work well in a garden setting.
The first is Swamp Marigold, Bidens aristosa var. mutica. This plant is the exceptional in that it has the largest ray flowers of the genus. Also, while the seed possesses the two teeth typical of the Bidens, these are not able to catch hold like the others. B. aristosa’s range extends from the Maine to Georgia and as far west as Oklahoma.
There are three other annual Bidens native to the Northeast US worth mentioning here. All of these grow 3-4 feet tall and prefer moist to wet soils.
- Smooth Bidens, B. laevis, has flowers that are slightly smaller and nod downward when in full bloom. Seeds are available from Native Ventures in Louisiana.
- Nodding Beggarticks, B. cernua, also has smaller flowers, but the bloom starts as early as June, extending to Septmeber.
- Northern Tickseed Sunflower, B coronata. For the taxonomists out there there corrected name for this plant is B. trichosperma, but it will take some time for this to be updated. Seeds for these last two plants are available from Prairie Moon Nursery.
I will be trying out the Northern Tickseed this year and comparing it to the Swamp Marigold. One thing I will watch for is how popular the flowers are with pollinators. Northern tickseed is a Massachusetts native, while the swamp marigold, while found in the wild, is not listed as indigenous to Massachusetts.
The last member of the genus I will mention here is Apache Beggarticks. These are low growing perennials originally found growing in open fields in southern Arizona and into Mexico. As the species, this plant has small yellow flowers; however, a number of larger flowered cultivars have been developed that perform well as annuals in gardens here in the Northeast. The species name ferulifolia is a reference to the fennel-like foliage.