Apply the last fertilizer application prior to July. Fertilizing in late summer may encourage new growth and prevent the plant from preparing for dormancy during winter.
Cut the stalks of all spent flowers back to the crown of the plant.
Remove yellow, wilted, or dead leaves.
Rake leaf litter and dead material out from under and around the plant. Slugs, pests and diseases love to hide in decomposing material.
Apply a thin layer of mulch carefully in the fall. Wait until several hard frosts have occured, freezing the ground to about 3 inches deep. Remove mulch from around the crown as soon as the soil begins to thaw, or you may provide a home for pests and conditions ripe for crown rot.