This plant showed up in Wild Ones Fox Valley Area Chapter member’s prairie this summer. At first sight it looked like a member of the native Marsh Mallow (Hibiscus moscheutos), but as I looked more closely at the leaves, it was quite different. I believe it is the non-native Musk Mallow (Malva moschata) which is at home in the Mediterranean and western Asia.
Marsh Mallow’s leaves are three-lobed, while the Musk Mallow leaves are deeply cut and palmately lobed. Their saucer-shaped blossoms are similar in size to the Marsh Mallow’s, but their basic structure is actually quite different. The Musk Mallow’s crepe-like petals are cleft to blunt-ended, while the Marsh Mallow’s are rounded. Like their cousin the hollyhock from China, they both grow blossoms all along the stem.
Here in the USA, Musk Mallow grows primarily in the northeast and northwest, and can be considered an invasive species in locations with temperate climates.
Rose Mallow likes disturbed habitats (anthropogenic) while Marsh Mallow likes marshes and shallow water.
Thank you Tim McKeag for this interesting topic.