Bidens frondosa thrives in consistently moist to wet soil conditions, often found in disturbed, damp areas. While it can tolerate some drier periods once established, regular watering is beneficial, especially during prolonged dry spells. Ensure the soil remains damp but not waterlogged to support vigorous growth throughout its annual lifecycle.

Pruning Bidens frondosa is typically not essential for its health or growth, given its annual lifecycle. However, if you wish to manage its spread or maintain a tidier appearance in a specific area, you can cut back plants before they set seed. This is particularly useful if you consider it a weed and want to prevent its prolific self-seeding. Otherwise, allow it to complete its natural cycle.

Bidens frondosa is most effectively propagated by its abundant seeds. These barbed achenes are naturally dispersed by clinging to animals, clothing, or carried by water. For intentional propagation, collect mature seeds in the fall. Sow them directly into moist, disturbed soil in early spring after the last frost. The plant readily self-sows, making it easy to establish new generations without intervention in suitable environments.

Repotting is not a relevant care practice for Bidens frondosa, as it is an annual plant that completes its entire life cycle within a single growing season. It is typically grown directly in the ground or in naturalized settings rather than in containers that would require transplanting. Once the plant has flowered and set seed, it naturally dies back, and new plants emerge from self-sown seeds the following year.