Bidens frondosa Bidens frondosa fruits with mm ruler on right. Bidens frondosa fruits with mm ruler on right. Bidens frondosa seedling germinated within a growth chamber set at a 25/15°C (77/59°F) day/night temperature with a 12-hour day photoperiod of cool-white fluorescent light. Bidens frondosa seedlings. Bidens frondosa seedlings. Bidens frondosa seedlings growing in 48-cell liners at the Berry Seed Bank research greenhouse located in Portland, Oregon. Bidens frondosa rootball of seedlings growing in 48-cell liners at the Berry Seed Bank research greenhouse located in Portland, Oregon. Bidens frondosa plants grown in 4-inch containers at the Berry Seed Bank research nursery located in Portland, Oregon. Bidens frondosa with rootball for plant grown in a 4-inch container at the Berry Seed Bank research nursery located in Portland, Oregon.