Spanish needles prefer consistently moist soil but can tolerate periods of dryness once established. Water thoroughly when the top 2-3 cm of soil feels dry. Avoid waterlogging, as this can lead to root rot.

Reduce watering frequency during cooler months when growth slows.

Pruning is primarily for shaping and encouraging bushier growth. Pinch back young plants to promote branching. Deadheading spent flowers can prolong blooming and prevent self-seeding if unwanted.

Light pruning can be done anytime to maintain desired size and form.

Spanish needles are easily propagated by seeds. Sow seeds directly in the garden after the last frost, or start them indoors 4-6 weeks prior. They also readily self-seed in favorable conditions.

Cuttings can also be taken in spring or early summer and rooted in moist soil.

Repotting is typically not necessary for Bidens bipinnata as it is often grown as an annual or short-lived perennial.

If grown in containers and it becomes root-bound, repot into a slightly larger container in spring before active growth begins. Use well-draining potting mix.