Eupatorium capillifolium is drought-tolerant once established. Water deeply during prolonged dry spells, but avoid waterlogged conditions. Allow the soil to dry out between waterings to prevent root rot.

Generally, natural rainfall is sufficient in many climates, making it a low-maintenance option.

Deadhead spent flowers to encourage reblooming and maintain a tidy appearance, though this is not strictly necessary for the plant's health.

Cut back the plant in late winter or early spring before new growth emerges to manage its size and shape. This also removes any lingering dead foliage.

Eupatorium capillifolium is easily propagated by division of established clumps in early spring or fall. Stem cuttings can also be taken in late spring or early summer and rooted in moist soil or a propagation medium.

Seed propagation is also possible, sown in autumn or early spring.

As a vigorous perennial, Eupatorium capillifolium generally does not require frequent repotting. If grown in containers, repot every 2-3 years in early spring into a slightly larger pot with fresh, well-draining potting mix to prevent it from becoming root-bound.