Venice mallow (Hibiscus trionum) is a summer annual forb that has a spreading profile and is native to Europe. The seeds are dark brown and can remain viable for 50 years. The cotyledons are round with hairy petioles. The first true leaves have toothed margins and are alternate. Leaves are alternate and divided into 3 to 5 distinct lobes. Margins on the lobes are toothed. The leaves are approximately 3 inches wide and long The upper surface of the leaf is not hairy, on the underside of the leaf hair is present. Flowers are a light sulfur to yellow color with a red to purple center. Flowers only last a couple of hours and are up to 1½ inches in diameter. The 5 petal flowers appear from July through September. The stems are erect, hairy, branching near the base, and are 10 to 18 inches tall.
Venice mallow Fact Sheet