A wildflower that thrives even in dry conditions, red feathers (Echium amoenum) have fringed 12- to 15-inch flower spikes in a beautiful raspberry-crimson color, Fradkin says. Pinch off spent blossoms to keep them blooming, but hold off late in the growing season to encourage reseeding.

Also known as woodland tobacco,  Nicotiana sylvestris has a floral scent that is reminiscent of jasmine. Southern gardeners love its pendant clusters of trumpet-shaped white flowers, which resemble shooting stars and bloom from early through mid-fall.

This tropical perennial produces big, pink blooms with stunning red eyes from July to September. "The flowers are humongous," says Dawn Fradkin, a horticulturist with Colorado State University Extension in Arapahoe County, where intense sunlight and clay soils can be a challenge for gardeners. "They're just striking for our area and our environment," she says.

Globe thistle (Echinops) produces ball-shaped, bluish-purple blossoms that add a playful touch to your garden. Their height and whimsical nature make them look as though they're dancing above everything else, Whitinger says. These tough little blooms hold their own in arrangements, too.

Decades of dedicated breeding have produced nearly 100,000 different varieties of daylily (Hemerocallis). Newer selections with 44 chromosomes—twice the normal number—have bigger flowers and bigger, darker green leaves, so you get a much bolder statement in the garden, says Whitinger. Among his favorites are strawberry candy, which features yellow-and-pink blooms, and Webster's pink wonder, which has 13-inch flowers with spidery petals and a gorgeous chartreuse center.

This bulb perennial's massive flowers bloom from mid- to late summer. They're striking in cut arrangements, where they can hold their own for nearly a week. Bloom colors range from sumptuous tangerine and electric purple to the prettiest pale pinks. Want even more drama? Dinner plate dahlias have enormous blooms that can measure 10 inches across.

Buds on this perennial inflate like living balloons, opening into large bell-shaped flowers from early spring through late summer. In addition to the super-cool periwinkle hue, astra blue (Platycodon grandifloras 'Astra Blue') also comes in pink and white.

Just about any hydrangea variety will add drama to your yard, but there's something special about panicle hydrangea (Hydrangea paniculata). This flowering plant grows massive cone-shaped flowers that bloom on new wood and put on quite the color show: Flower heads emerge as white or green in mid-summer, fading to gentle pink or red as the season draws to a close.

Grown as a woody shrub or tree, angel's trumpet (Brugmansia) can thrive outdoors in warm climates and in containers in cold ones, says Dave Whitinger, the executive director of the National Gardening Association. Its cone-shaped flowers—as big as 24 inches long, depending on the cultivar—dangle downward like trumpets from the heavens.

Focal points in your landscape add visual order by telling the eye where to look first. You can create them with hardscaping, like a bench or statue, or with a flowering plant that's so big, colorful, or surprising that it's impossible to ignore. As you design your garden, experts say to consider adding these showstoppers to your space.