This one-of-a-kind mallow is a knockout, with huge, textured leaves and towering stems of fragrant flower clusters. The small, white flowers open in the morning and close at dusk from early summer to early fall. Glade mallow is uniquely suited to moist or wet locations in full or part sun. It’s sometimes used in restoration projects to stabilize waterways because it spreads by rhizomes and thrives in wet, rich soils. These are traits to keep in mind if you want a truly low-maintenance plant; give it room to spread in soils that remain consistently moist. The plant also benefits from a sheltered spot, because the tall stems are prone to toppling over during high winds. In addition to delivering robust beauty to wet areas, glade mallow attracts native bees and flies and offers cover for a variety of wildlife. It’s also a host plant for one obscure owlet moth. Jim McCormac, author of the blog Ohio Birds and Biodiversity, shares an entertaining story of his personal encounter with the rare larvae at https://jimmccormac.blogspot.com/2008/07/glade-mallow.html.  
 
Glade mallow is highly distinctive in appearance, habit, and within its own family. The palmated, green leaves lend a slightly exotic flavor, and the pure-white flowers, while smaller than other mallow blooms, are numerous and positioned a couple of feet above the foliage. The overall effect is stunning and bold, especially when planted en masse, which is usually a wise choice with this dioecious mallow. Because the male and female flowers are on separate plants, groupings of several or more individuals will ensure fruit production. The difference between the two types of flowers is charming; both have waxy, brilliant-white petals, but a bouquet of curly styles emerges from female flowers, while male flowers feature a column of stamens topped by a ball of pink-tinged anthers. The resulting fruits are pinkish-brown, pumpkin-shaped containers that eventually split open to release their seeds. Glade mallow has no close relatives alive today, and it’s the only surviving member of its genus. Napaea is said to come from the Greek word nape, which means 'of the glade.' Dioica translates as “two houses,” referring to the plant being dioecious. Glade mallow is the only strictly dioecious species in the Mallow family that is native to the Western hemisphere, according to Minnesota Department of Natural Resources. Its native range is restricted to a handful of states, including Ohio, in the northern part of central and eastern US. 
 
Native habitats include low-lying, open grounds of alluvial soils of floodplains; wet prairies and roadsides; moist woodlands; and marshes. Use along banks of water features, in rain gardens, and in lower areas. Companion plants include cup plant, rattlesnake master, Riddell’s goldenrod, and spotted Joe-pye weed. 
 
Plant Characteristics:
Grows 3-6’ tall and 2-3’ wide; flowering stem grows up to 8’ tall. 
 
Prefers full to part sun.
 
Prefers moist to wet, rich soils. 
 
Tight, branching clusters of short-stalked flowers bloom June-August on side stems at upper part of the plant. Flowers are 3/4” across with 5 white, deeply cut, oval petals. Female flowers have a cluster of thread-like styles atop a white ovary.  Male flowers have a cluster of stamens in the center; the filaments are fused into a column with the pinkish anthers in a ball at the tip. The tubular calyx has 5 pointed, green lobes. Female flower forms a round cluster (schizocarp) of up to 10 wedge-shaped, capsule-like segments (mericarps), each containing a single seed that matures from green to dark brown from August-September. 
 
Alternate leaves are 4-12” long and up to 18” across, round in outline, with 5 to 9 deeply palmated, coarsely toothed lobes. Leaf surface is mostly hairless and underside has fine hair. Lower leaves are long-stalked, with leaves becoming smaller and shorter-stalked as they ascend the stem. At the base of the leaf stalk is a pair of lanceoate, leaf-like appendages up to 1” long that wither away as the plant matures.
 
Erect, ridged stems are unbranched except in the upper section. Stems are sparsely hairy and often coated with a waxy bloom. The root system is a hollow taproot. Plants may form colonies from spreading rhizomes.
 
Wildlife Value:
Host plant to Bagisara gulnare, a rare species of owlet moth. Flowers are cross-pollinated by bumble bees, sweat bees, and solitary bees. Syrphid flies also visit. Provides cover for a variety of animals and insects. Deer browse the plant.
 
Medicinal, Edible, and Other Uses:
The Meskwaki used the root to treat hemorrhoids, ease childbirth and women’s issues, and reduce swelling. 
 
The plant, especially the roots, contains mucilage, which is rich in protein and carbohydrates. It has been used as a compress for various external injuries. It is also made into a tea to treat sore throats, coughs, and constipation.
 
The white marshmallow confection eaten today was originally made from the sap of the roots of mallows grown in marshes.
 
Various foragers indicate that the entire mallow plant is edible, from roots to fruits. The rather bland leaves are loaded with calcium; magnesium, potassium, and vitamins A, B, and C. They can be used raw in salads, sautéed with oil and garlic, baked, or used similar to okra to thicken soups and stews.