But it turns out that not all acanthus species are so sensitive. While A. mollis grows only in USDA zones 7-10, the species A. spinosus is the hardiest species and is comfortable in zone 5.

Acanthus comes from the Greek word for thorn but most of the plants in question are hardly thorny. The family name is taken from Acanthus (one of its genera), some of whose species have spiny leaves.

Most of them thrive in half-day sun, although they also do well enough in full sun and a species known as bear’s breeches (Acanthus mollis) actually prefers shady locations.

In my garden, I saw two plants thriving without supplemental water: Acanthus mollis and Chasmanthe floribunda. Carvings of Acanthus with its deeply lobed leaves and bold flower stems grace the ...