Horticulture/Veronica arvensis

Veronica arvensis -- known variously as Corn Speedwell, Common Speedwell, Speedwell, Rock Speedwell, or Wall Speedwell -- is a low-growing herb native to Europe, but also an invasive weed in North America.

Description
Low-growing, somewhat hairy plant with small dark-blue flowers. Flowers from late spring through early autumn.

Ecology
Spread by the small seeds, usually with the help of foot traffic. Common in nursery containers.

Uses
Has some medicinal uses.