Plant of the Month July 2019: Swamp Rose-mallow
Swamp Rose-mallow (Hibiscus moscheutos), also known as Eastern or Crimson-eyed Rose-mallow and one of our showiest native wetland plants, is in full bloom right now. It is found in both freshwater and tidal marshes along our rivers and creeks, open marshes and other damp areas. A statuesque, shrub-like perennial that grows 3-7’ high on sturdy stems, the plants create a spectacular display as their exotic large blooms wave above the water from mid-July to September.
Swamp Rose-mallow is topped with 4-6” diameter flowers that have five silky white, or sometimes pink, petals surrounding a crimson eye. Like other members of the Mallow family, their reproductive parts are held on a central columnar structure studded with numerous stamens below five styles with knobby, pollen-catching stigmas at their tips.
Although individual flowers last only a day, a parade of new buds continue to open for over a month putting on a dramatic show that delights gardeners and pollinators alike. The distinctive, 1” ovoid capsules that develop after the flowers have a ring of dark-brown, sequentially ripening seeds. Swamp Rose-mallows will reseed and spread in moist soils.
The plants have light-green, oval- or deltoid-shaped leaves with rounded teeth along the margins. They grow in full sun to part shade in loamy to sandy soils with consistent moisture. They are slightly salt tolerant and perfect for planting in low damp spots along ponds, shores, meadows, or even in large containers. Japanese beetles and aphids can sometimes be problematic, especially in dry sites, but can be picked off or deterred with a hard spray of water.
Swamp Rose-mallows have long been favorites in perennial gardens. They attract hummingbirds, orioles, and a variety of long-tongued bees to their nectar as well as hosting caterpillars of at least 28 species of moths and butterflies, including the lovely Painted Lady, Common Checkered Skipper and the amazing Delightful Bird Dropping Moths!
Amaze your friends and neighbors: plant several showy Swamp Rose-mallows in moist areas and enjoy the mid- to late-summer extravaganza!
Submitted by Betsy Washington, Northern Neck Chapter, Virginia Native Plant Society