Plant perennial loosestrife in moisture-retentive soil enriched with plenty of organic matter. Choose a sunny or lightly shaded position and keep the soil consistently damp, as these plants dislike drying out. In spring, apply a 5-7cm (2-3in) mulch of well-rotted compost or manure around the base to feed the plant and help retain moisture.

Lift and divide congested clumps every few years in early spring or autumn to rejuvenate growth and maintain vigour. These hardy perennials provide long-lasting colour in damp borders or by ponds, where they thrive with lower maintenance requirements once established.