Asiatic dayflower Commelina communis L.
Family: Commelinaceae – Spiderwort family
Life cycle: Annual
Native status: Introduced from eastern Asia
Habitat: Gardens, crop fields. Prefers moist areas.
General description: Prostrate or semi-erect growth habit, stems reaching lengths of 1 to 3 feet. Hairless, glossy alternate leaves with parallel veins. The base of leaf blade clasps the stem with a membranous sheath. Flowers over an extended period; however, individual flowers last a single day.
Key ID traits: Glossy leaves with parallel veins and sheath that wraps around stem. Flowers have two blue, circular petals that have been compared to Mickey Mouse ears.
Similar species: Bengal dayflower is a similar species that is a problem in Southeast U.S. Wandering jew is a houseplant in the spiderwort family with a similar growth habit. The growth habit and leaf shape of Asiatic dayflower is similar to Pennsylvania smartweed and other smartweeds, and at casual glance the leaf sheath can resemble an ochrea, so some people mistake A. dayflower for smartweed.
Miscellaneous: Asiatic dayflower is tolerant of glyphosate, and first caused problems in crop fields following the introduction of glyphosate resistant soybean. The name comes from the flower petals typically lasting only one day. A third, much smaller white petal is found under the two blue petals.