Daylilies
Hemerocallis hybrids, perennials. For months of trouble-free color, one day at a time, nothing beats the perennial daylily. Daylilies, as their name suggests, produce colorful flowers that last but a day, but they never stop blooming, pumping out flower after flower, for months on end. Available in endless colors including yellow, pink, red, orange, purple, white, peach and bi-colors of all descriptions. Plant in full sun and moist soil.
Liatris
cold-hardy summer-blooming bulbs. Great for purple pizzazz, these 4- to 5-foot tall spikes, also known as gayfeathers, are magnets to butterflies, who love their fuzzy-looking florets. Avoid planting in soggy soil; if situated in partial shade, they will provide vibrant blooms July to August. For best effect, plant in groups of 15 or more. The scariosa variety sports white, rose, or lavender blooms.
Heliopsis
perennials. A North American native, this nonstop bloomer (June through September) is sometimes called the false sunflower. But it's much better suited to sunny borders—growing to a manageable four feet, with brilliant yellow flowers that actually look more like daisies. Cut bouquets regularly! A stand produces so many flowers your garden won't miss them!
Tuberous Begonias
tender summer-blooming bulbs. No shade-loving flower is more velvety than the begonia. With its luscious multipetal flowers in the richest shades of deep to pastel pink, red, yellow, peach, champagne, white, and orange, begonias often look too good to be real. And they bloom and bloom and bloom. There's even a variety named "non-stop begonia."
Lilies
cold-hardy summer-blooming bulbs. These glamour gals of the garden are winter-hardy bulbs that can be planted in either spring or fall. There are numerous types to choose from, with blooms from mid-summer through late fall. For different looks and bloom times, select an assortment of Asiatic, Oriental, longiflorum, trumpet, or hybrid species types. Plant in full sun for best performance in the garden or containers.
Cannas
tender summer-blooming bulbs. Cannas do have flowers but it's their dramatic foliage that gets the applause. Five feet tall and flamboyant, cannas are tropically lush, with leaves in green, burgundy, bronze, brown, or multistripes. Their flowers, big and brassy, simply unfurl like angel wings and then fade and flutter away. Cannas thrive in full sun and hot weather.
Dahlias
tender summer-blooming bulbs. Dahlias will dazzle your late-summer garden with intoxicating color and form. These sun lovers come in all sizes, on stems ranging from 12 inches to 5 feet tall. Flowers can be small and spunky or large as dinner plates, in nearly every color except true black or blue. Plant them in full sun in the garden or containers.
Images courtesy of The Netherlands Flower Bulb Information Centre