Bidens is a genus of plants, many of which are wildflowers native to the United States. Common members of this family are Bidens alba and Bidens bipinnata, both better known as Spanish needles. They are quite aggressive and produce up to 6,000 seeds per plant, which stay viable for up to five years in the soil. If you want to get rid of the Bidens wildflowers growing in your landscape, it is possible but takes years of persistence.
Clip off the tips of the flowers and immediately throw them in the trash. Do not send them to your compost or to the yard waste area of a landfill, where their seeds may cause further problems for you or someone else. Ideally, you should get rid of Bidens wildlfowers before they flower.
Wet the soil with about a 1/2 to 1 inch of water. Wait until the next day to pull up the Bidens wildflowers. It is easier to remove the roots when the soil is moist.
Pull the wildflowers out of the moist soil, grabbing the plants near the bottoms. They snap easily so pull slowly and deliberately to get as much of the roots as possible.
Spot treat Bidens wildflowers with a ready-to-use formula of glyphosate, which is easy to use, as an alternative to pulling them up. Do not spray the herbicide on anything else. Read the instructions prior to applying glyphosate.
Continue to rid your landscape of Bidens wildflowers. They will likely return so more pulling or applications of glyphosate will be necessary.
Tips & Warnings
- Mow Biden wildflowers frequently. This thins them out and prevents them from flowering and reseeding.