Long blooming and repeat blooming perennial flowers form the backbone of garden design. Large blocks of color add impact to a garden and the best way to achieve that is with long blooming perennial flowers, like Achillea, Coreopsis and Coydalis. Here are some more to consider.
Dianthus (Pinks)
USDA Zones 3 - 9 - Bloom Span: 2+ Months
While most Dianthus have a long natural period of bloom, many will rebloom with some deadheading. Several varieties are also evergreen and make nice edging plants. Dianthus does well in any well-drained soil, though it prefers a slight alkalinity. They don't tend to live very long and should be divided or seeded regularly.
GOOD CHOICES: Dianthus gratianopolitanus 'Bath's Pink', D. g. 'Cheddar Pink', D. deltoids (Maiden Pink)
Dicentra formosa & Dicentra eximia (Fringed Bleeding Heart)
USDA Zones 2 - 9 - Bloom Span: 3+ Months
Unlike the common bleeding heart (D. spectabilis), cultivars of the fringed species will repeat bloom for most of the summer. D. formosa is a western native while D. eximia is able to handle the heat and humidity of the eastern U.S. The fringed bleeding hearts are smaller plants than D. spectabilis and the flower is not as pronounced a heart shape, but the gray-green ferny foliage and abundance of flowers make it a prize. Most self-seed.
GOOD CHOICES: 'Alba' has a pure white flower
Echinacea purpurea (Coneflower)
USDA Zones 3 - 9 - Bloom Span: 2-3 Months
Having a long bloom period is just on of Echinacea's many attributes. Coneflowers are extremely drought tolerant, attract birds and butterflies and the intense color adds punch to any garden. The tall stalks are self-supporting, unless they've received so much water they become floppy. They require good drainage and full sun. Deadheading will prolong the bloom period. Although Echinacea is slow to spread, division is the best way to get the cultivar you want. The seed heads can be left on through the winter and will provide a treat for neighborhood birds.
GOOD CHOICES: Echinacea purpurea 'Magnus", E.p. 'Fragrant Angel', E. "Art's Pride'
Gaillardia (Blanket Flower)
USDA Zones 2 - 9 - Bloom Span: 3-4 Months
Daisies on caffeine. Gaillardia's yellow petals around a burgundy center are impossible to ignore in a garden. All they ask is full sun and they will keep on blooming all summer. Too mush shade and the stems begin to flop. In most cases, deadheading is not necessary for continual bloom, but it can make the plants look tidier. Gaillardia is another short-lived perennial and should be divided or seeded often.
GOOD CHOICES: Gaillardia x grandiflora, Gaillardia 'Goblin' (dwarf), G. 'Burgundy', G. 'Monarch'
Kniphofia (Red Hot Poker)
USDA Zones: 5 - 9 - Bloom Span: 3+ Months
The spiky, bottle-brush flowers of Kniphofia are beacons for hummingbirds. Although they look like tough customers, Kniphofia actually requires a bit of winter protection in cooler zones. They are also a bit fussy about liking moist conditions in the summer, but well-drained soil for the winter months. Full sun is generally necessary for ample blooms. Kniphofia does not divide or transplant well, although you can usually get away with removing and replanting the young side shoots of the plants.
GOOD CHOICES: Any of the hybrids. Kniphofia ''Primrose Beauty' is especially hardy.
Liatris (Gayfeather, Blazing Star)
USDA Zones 3 - 9 - Bloom Span: 3 Months
Liatris are easy to grow and texturally unusual. The thin, spiky leaves jut off the stems all the way to where the rosy-purple flower spikes begin. Unlike most spiky flowers, Liatris blooms from the top down. Liatris can handle just about any type of soil, but the richer the soil, the more likely they'll need staking. They'll grow in full sun or partial shade. Liatris is long lived and doesn't often require division. They will self-seed, but generally don't take over.
GOOD CHOICES: Liatris spicata (Spike Gayfeather) comes in white, pink and shades of purple
For still more choices...
