Callirhoe involucrata

While many perennials are valuable for even a brief moment of bloom time, I find myself focusing more on those long-blooming perennials that encourage the exclamation of “I can’t believe that’s still blooming!” The purple poppy mallow (Callirhoe involucrata) is such a plant and continues to amaze me every year with not only the vivid, cerise-magenta blooms over many months but a robust growth rate and amazing durability in tougher soils. This drought-tolerant member of the Malvaceae family is native to the Central United States and prefers well-drained clay, loam or sandy soils in full sun situations. While purple poppy mallow doesn’t get much taller than 9 inches in height, this mat-forming perennial rambles and sprawls over 36-60 inches in a single season with dark green, palmately lobed, hairy leaves. The plant can be pinched back to control size and removal of spent flowers will help encourage quicker rebloom. The long tap root provides excellent drought tolerance but makes successful transplanting of established plants a bit more challenging.

The solitary, upward-facing, five petaled flowers are between 1½ and 2½ inches wide with a white center. Forming a cup or chalice-shape (hence the common name of “wine cups”) these bright flowers start in mid-spring, peak in summer and then appear sporadically until hard frost. The flowers open in the morning and close at night. After pollination, the flowers remain closed. Purple poppy mallow is a “gentle reseeder” so be aware of progeny. Bees and butterflies will visit for flower nectar although unfortunately rabbits and deer can be problematic “nibblers”.

In the hottest and driest of summers, this plant may go into a temporary dormancy but will generate new growth after soaking rains. Easiest grown from scarified seed, this perennial is quick to establish and settle into the garden. It’s no surprise that C. involucrata was a 1999 Plant Select Winner and received the Award of Garden Merit from the Royal Horticultural Society. Well grown plants have very few issues although crown rot may occur in in poorly drained soils and there is some susceptibility to rust. Closely related (and worth seeking), the standing wine cup (C. digitata, Zones 5-8) has a similar flowering appearance and timing but reaches 24-48 inches in height.