It is a winter annual so most likely it germinated last fall or in very early winter, and is just visible now. It also comes with several lookalikes, including ivyleaf and Persian speedwell, and on first glance, could even be confused with mouseear chickweed.
Corn speedwell has more serration of the leaf margins than that of ivyleaf and is covered in fine hairs, whereas Persian speedwell is glabrous or without hairs.
As corn speedwell matures, leaves will tend to be longer and narrower with a smoother margin. Mouseear chickweed will have hairs on the upper leaf surface and midvein of the underside, however the leaf margin is entire, or without serration.
The final identifier is mouseear chickweed will have white flowers, and the speedwell will have a pale bluish to a light purple flower.
Preventative measures are best when applied in the late summer to early fall, and most conventional pre-emergent herbicides perform very well. Most traditional post-emergent herbicides will get good to excellent control, but this weed can be a little tricky.
First, because of the tiny leaf surface, excellent coverage of sprays is required.
Second, due to the pubescent or hairy leaf surface, herbicides applied without surfactants may not get sufficient leaf surface contact for outstanding control.
Lastly, weed and feed granular materials should not be considered an option because leaf contact would be difficult at best. Non-selectives in beds are the best option when you see these weeds springing up.
Please contact the Ewing Technical Services Team with questions and for help with weed identification.