Polkadots

Dyschoriste linearis ( Polkadots )
A groundcover perennial, reaching up to 1 x 2.5 feet in size, that is native from western Oklahoma to western Texas.
The oppositely-arranged, oblanceolate leaves, up to 2.7 inches in length, are bright green.
The lavender-purple ( purple striped throat ) flowers, up to 1.1 x 1 inch in size, are borne during late spring, repeating during late summer if rainfall is adequate. The flowers are borne from the leaf axils. They attract butterflies and honey bees.
Hardy zones 7 to 9 in full sun to partial shade on just about any well drained soil. It is tolerant of extreme heat, drought, alkaline soil and temporary flooding.

* photo taken on Aug 23 2014 @ U.S. Botanical Garden, Wash., DC