Napaea dioica aka Glade Mallow

Napaea dioica, or glade mallow, is in the mallow family. This tall plant lives for years. It comes from the central and eastern United States. It grows in scattered sites, not one broad, unbroken range. Wild plants grow by rivers and in moist, open ground. Sources differ on how far east its native range goes. Kew lists Maryland as its eastern edge. Chicago includes Vermont and Pennsylvania. Missouri questions old records from Pennsylvania and Virginia. Those records may name the wrong plant.

In gardens, glade mallow grows 4–8 feet (1.22–2.44 metres) tall. Its full spread reaches about 3 feet (0.91 metres). It has a strong, upright form and coarse growth. Its height makes it stand out among lower garden plants. The large leaves are palmate: their lobes spread like fingers. Each leaf has five to nine lobes and toothed edges. Leaves grow smaller toward the top of the plant.

Many tiny white flowers form a large, branched panicle, or flower cluster. Missouri gives June through August as the main bloom season. Chicago notes a show of flowers in July. The blooms have scent, and Missouri rates them as showy. Each plant bears either male or female flowers. The stamens in male blooms join to form a column. Female blooms have long, white styles. Grow several plants together if you want female plants to fruit. This helps them get pollen from another plant to set fruit. Missouri notes that the fruit adds to the plant's display.

Give glade mallow moist to wet loam that does not dry out. It accepts full sun but grows best in part shade. Shelter helps keep strong winds from harming its tall growth. Its need for steady moisture limits its use in dry beds. Wet soil, in contrast, suits this species. Missouri lists it for USDA zones 3–8. Chicago gives a wider range of zones 3–10. Both sources place it in moist garden sites with some sun.

Use glade mallow in damp garden areas with part shade. Its height, large leaves, and white blooms give it most of its appeal. Chicago grows it in native plant gardens and waterfall gardens. Missouri says it needs little care. It reports no serious pest or disease problems. The supplied sources give no food uses or facts on toxicity. They thus do not show whether any part is safe to eat. The plant is uncommon, but that fact alone does not place it in an IUCN threat category.