Growing perennial flowers on the coast can be challenging. Sandy soil, high winds and salt spray can fast derail efforts at cultivating flowers that will re-grow year after year. Although many varieties of perennial flowers are slightly salt tolerant, varieties known to be highly or moderately salt tolerant are the best choice for a perennial flower border located on the coast.
Because of the severe winters on the coast of Maine, which lies in USDA Hardiness Zone 5, choose salt tolerant varieties that are known to be hardy and will survive the severe winters in this area.
Tolerant of salt spray, sandy soils and drought, blanketflower (Gaillardia pulchella) is native to the United States. It produces red daisy-like flowers with yellow rims and prominent centers on 18- to 24-inch high plants. Blanketflowers bloom from May through September. Gaillardia is a very adaptable plant and will easily adjust to most growing conditions, but prefers full sun to partial shade.
Widely planted on public land because of its ease of cultivation, daylilies (Hemerocallis spp.) produce lily-like flowers all season long in sun or light shade. Many varieties are available, with heights that range from a few inches to several feet. Flower size ranges from 2- to 8-inches wide. Most cultivars are in the yellow-orange-red color family. Although they prefer slightly acidic soil, daylilies will grow in most types of soil as long as it is well-drained. Plant in early spring or fall when the weather is cool. Keep them well-watered during their first year of life in your garden and they will grow, bloom and multiply for many years to come.
A sub species of dianthus collectively known as 'Cheddar Pinks' (Dianthus gratianopolitanus) is named for its native habitat in Cheddar Gorge, England. They grow to a height of about 12 inches with an equal spread. Gray foliage highlights its solitary, fragrant pink flowers. Grow them in full sun to partial shade in rich, well-drained soil. Cheddar pinks are hardy in USDA Zones 3 through 8.