Type: Annual grass relative
Size: To 30 inches tall and wide
Where It Grows: Sunny or shady landscape areas
Appearance: Dayflowers have dark green leaves sprouting from a stem and brilliant blue flowers through the summer.
Control: Mulch the garden to prevent weeds or use a preemergence herbicide in spring. Pull weeds by hand or spot-treat with a nonselective postemergence herbicide.