Dr. Kevin Korus: Battling an obnoxious noxious weed
One of the most tenacious weeds to ever enter Florida is the Benghal dayflower (Commelina benghalensis). This spreading ground cover is legally classified as a noxious weed and can lead to quarantines if found in commercial nurseries. For the homeowner, the weed can invade the garden, landscape and even the lawn.
The adage “an ounce of prevention is worth a pound of cure” is especially true in this case. It is important to be able to identify this weed and recognize its presence early on. Benghal dayflower is commonly misidentified as spreading dayflower (Commelina diffusa) and Asiatic dayflower (C. communis). Although control methods do not differ greatly between the species, there are morphological characteristics that separate tropical spiderwort from the other dayflowers.
Stems are fleshy, succulent, covered in fine hairs and have a light green color. Young leaves are egg-shaped but become more pointed or lanceolate when they mature. Leaf margins are entire (smooth). Small white or red hairs may be present on the leaf sheath. Benghal dayflower leaves are wider and shorter than other dayflower species, and may contain hairs on the young leaves and petioles. Other dayflower species have leaves that are waxy, thick and glabrous (no hairs).
The flowers of Benghal dayflower have three petals; they are purple/lavender, while other dayflowers have blue flower petals.
Roots are fibrous but contain shallow rhizomes. The most unique feature of this plant is its ability to produce underground flowers. These flowers, which produce viable seed, appear as swollen nodes. No other dayflower species produce underground flowers.
Benghal dayflower typically germinates in June/July in Florida. It is a prostrate, spreading perennial with fleshy stems that root readily at the nodes. Some stems may be erect to about 12 inches. This plant can form a dense mat if not managed.
Mowing is not an effective means of control as broken stems can regenerate into new plants. Tillage also may serve to spread the plant because of the presence of the underground seeds. Hand removal of the entire plant is the most effective means of control but is labor intensive and not practical over a large area. Herbicides (i.e. glyphosate, 2, 4-D, triclopyr) provide temporary control but need to be applied repeatedly until the weed is exhausted. For more information on Benghal dayflower, see UF/IFAS EDIS Publication ENH1085.
— Dr. Kevin Korus is the Agriculture and Natural Resources Extension Agent for UF/IFAS Extension Alachua County. Contact him at kkorus@ufl.edu or 955-2402.
This article originally appeared on The Gainesville Sun: Dr. Kevin Korus: Battling an obnoxious noxious weed
