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.
I ended up pulling these plants out. I could see they had spread aggressively from a neighbor and I just didn’t want the problem to grow. My conclusion is that these plants are invasive.
Does anyone have any comments on Persian corn flower. It is sold and is quite common in the commercial nursery trade?
Persian Cornflower or Black Knapweed (Centaurea nigra) is a cousin of the Spotted Knapweed (Centaurea biebersteinii). These Knapweeds originate in Eurasia. Like most knapweeds, both are considered invasive species in Wisconsin and elsewhere in the USA and should not be sold.
Knapweeds like full sun and thrive in well-drained, limey soils. They bloom from June to September and you often see them lining the roadside edges as you drive about the countryside. The rose-colored thistle-like flowers are hermaphrodite (have both male and female organs) and are pollinated by bees, flies and lepidoptera, as well as being self-fertile. They produce great amounts of seed.