$4.50. Lots of blooms. Perennials, partial sun.

Add color and height to your summer borders with Mexican petunia, occasionally called ruellia. This easy-care plant grows 3 feet tall (though there are also dwarf varieties that stay shorter) and develops waves of blue, white, or pink petunia-like flowers through the summer. Mexican petunia is great choice for butterfly gardens because the colorful insects flock to its sweet flowers. Plus, several species of butterflies use Mexican petunia as a host plant for their larvae to feed on, so it's a must-have plant for butterfly gardens. Once established, Mexican petunia can often self-sow and spread quickly through the garden -- so plant it where you can keep tabs on it or in large container gardens.

Mexican petunia is deer resistant. Part sun to full sun.

Zones 8-11