Dwarf Willowherb prefers consistently moist soil. Water regularly, especially during dry periods, ensuring the soil does not completely dry out. Avoid waterlogging, as this can lead to root rot.

Aim for a thorough watering when the top few centimeters of soil feel dry to the touch.

Pruning is typically not essential for Epilobium obscurum, but can be done to maintain shape or remove spent flower stalks. Deadheading can encourage a longer flowering period and prevent self-seeding if unwanted.

Light trimming can be performed in late autumn or early spring to tidy the plant.

Epilobium obscurum can be propagated by seed sown in spring, either indoors or directly outdoors in a prepared seedbed. It also readily spreads via runners and rhizomes, making division of established clumps in spring or autumn a simple and effective method of propagation.

Repotting is usually only necessary if the plant becomes pot-bound or if it is being divided for propagation. Choose a pot that is slightly larger than the current one. Repot in spring, using a well-draining potting mix.

Water thoroughly after repotting to help settle the soil.