Acanthus montanus

Winter hardy to USDA Zones 7-10 where it may be grown in fertile, medium moisture, well-drained soils in full sun to part shade. Plants tolerate a wide range of soils except poorly-drained ones. Plants may not flower well in too much shade. Remove flowering stalks after bloom. Plants are evergreen in warm winter locations, but leaves will show considerable damage in colder winters near the northern edge of the growing range. Plants can spread invasively by creeping rootstocks, particularly in loose soils. Unwanted spread can be addressed by root barriers. Plants generally spread less in the northern parts of their growing range. Plants are best propagated from root cuttings taken in early spring, but may be grown from seed. Plants can be slow to establish in the garden (particularly if started from seed), but become somewhat difficult to eradicate once established since small sections of root left behind can sprout new plants. This plant is not reliably winter hardy to the St. Louis area. If attempted outdoors in St. Louis, it should be sited in a protected location and mulched.