Weed of the Month- August

Asiatic Dayflower (Commelina communis)

Provided by Master Gardener, Peter Russell

Family: Commelinaceae- Spiderwort Family

Life Cycle: Asiatic Dayflower is an introduced summer annual weed reproducing by seed.

Description: Asiatic Dayflower can be erect or sprawl across the ground like a vine. The root system is fibrous. This plant can root at the leaf nodes on moist ground, forming new plants vegetatively. At favorable sites, the Asiatic Dayflower forms colonies that can exclude other species of plants.

Stems: The stems are thick, swollen at the nodes, and often rooting when nodes come into contact with soil.

Leaves: The leaves are longer than they are wide and wider near the base of the leaf with parallel leaf veins.  Leaves clasp the stem at the base and have a membranous sheath around them. Hairs are often present in this area.

Flower: Occasionally, a single flower on a stalk about 1"-2" long is produced from the leaf axils consisting of two large blue petals and one small white petal. The blooming period occurs from mid-summer to early fall. Each flower blooms during the morning for a single day, hence the common name. There is no noticeable floral scent.

Fruit: Each flower is replaced by a seed capsule that has two cells, each cell containing two seeds. These seeds are dark brown or black and have a surface that is bumpy and rough.

Control and Management: Hand pull before plant grows large, making sure to remove all stem fragments.

References:
Virginia Tech Weed Identification Guide
UMass Extension Weed Herbarium
University of Maryland Extension
Illinois Wildflower
Photos: Randall Prostak, University of Massachusetts