Russian sage (Perovskia atriplicifolia) beats the heat with its cool haze of blue blooms. Adaptable to harsh conditions, it maintains color throughout the heat and attracts plenty of butterflies to the garden.
Older varieties grow tall and can get floppy if they're not grown in full sun. Look for newer dwarf selections such as 'Little Spire' or 'Lacey Blue' that stay standing up better.
Hardy hummingbird trumpet (Zauschneria arizonica) thrives in front of a sizzling south- or west-facing wall, where other plants would cook. The display of red-orange trumpets will spice up any garden. This plant earns its common name; the blooms, which appear in late summer and autumn, are almost irresistible to hummingbirds. Though butterflies and hummingbirds love it, deer and rabbits leave hardy hummingbird trumpet alone.
Sunset hyssop (Agastache rupestris), also called hummingbird mint, is named for its fragrant foliage (or the birds that love its colorful blooms). The reddish-pink flowers and finely textured foliage are indispensable in a water-thrifty garden. Like many plants that have fragrant foliage, hyssop is deer- and rabbit-resistant.
There are lots of varieties of hyssop. Anise hyssop offers lavender-blue flowers in late summer and early autumn; 'Tango' shows off golden-orange blooms; and 'Heatwave' offers brilliant pink flowers.
Learn more about hyssop.
Angelonia, also called summer snapdragon, earns kudos for its ability to thrive when the temperatures soar. This annual blooms on 18- to 24-inch-tall stems.
Some angelonia varieties are fragrant. Most bloom in shades of pink, purple, blue, and white. The Archangel series is known for extra-large flowers; the Serena series has a more compact habit, making it perfect for growing in hanging baskets.
Learn more about angelonia.
Hardy Ice Plant
Hardy ice plant (Delosperma spp.) has daisylike flowers that add pink, lavender, and yellow color to the garden in late spring and early summer. This succulent is a top pick for low-maintenance dry spots such as slopes or raised beds. It has rich green succulent foliage that almost looks like needles. The foliage makes a fine groundcover when the plants aren't in bloom.
Learn more about hardy ice plant.
Prairie zinnia (Zinnia grandiflora) is a native perennial that prefers sunny, hot spots, flowering with bright, deep-yellow blooms from late summer to frost. Native to areas of Texas, Arizona, New Mexico, Colorado, Oklahoma, and Kansas, it's a top pick for rock gardens or other spots that have good drainage.