Acanthus mollis is the technical name for the more whimsically titled Bear's Breeches. A tall, spiky plant full of lovely tongue-shaped flowers, this prolific perennial is hardy in zones 8 through 10. Protect it for the winter, and you will ensure cottage charm for shady garden spaces next year.
Divide Bear's Breeches in the fall if the crown has over grown the allotted space or to create new plants for blooming in the spring. Dig well outside the root ball with the round shovel or spading fork and carefully sever the ball in half or more equal pieces. Ensure each piece retains root and several points of growth origin.
Space new plants 4 to 6 feet apart to allow for mature growth.
Replant Acanthus mollis in holes slightly wider than the side of the new root section, filling around the clump with dirt. The crown of the plant should be at soil surface level.
Firm the soil to set the plant in place, but avoid tightly packing soil as it starves roots for oxygen and inhibits root development.
Water well after replanting. Decrease watering as the season draws to a close.
Remove dead plant material from the base of Bear's Breeches. Cut back foliage and spikes for the winter.
Mulch 2 to 3 inches over the perennial with an organic matter such as pine needles, wood chips, or leaf cuttings. Avoid mulching until temperatures have dropped and frost has set in because warm temperatures and mulch could create crown rot.