French marigolds, derived from Tagetes patula, include most of the dwarf cultivars, while the generally taller African cultivars arose from T. erecta. Hybridizing has also produced many cultivars with intermediate characteristics. As a group, marigolds grow 8 to 42 inches tall, as low mounds or erect bushes. The 1-to 4-inch flowers may be rounded, tufted, or shaggy puffs in shades of white, yellow, orange, mahogany, maroon, and rust. Dark green leaves are dense, ferny, and often strongly scented. Other worthy marigolds include the signet group from T. tenuifolia, which has 8-inch mounds of lacy, lemon-scented leaves and ½-inch red, orange, or yellow single flowers. T. filifolia, Irish lace marigold, is grown for its dense 1-foot mounds of delicate foliage.
How to Grow
Marigolds are so easy to grow that they’re often a child’s first garden success. Given warmth, they grow quickly. Sow seed indoors a few weeks before the last frost (especially recommended for the taller cultivars) or direct-seed when the soil is warm. Give them full sun in average soil and moisture for best results, but don’t worry if the soil is poor or dry. Excess fertility may promote lush growth, few flowers, and soft stems, especially in the tall cultivars, which then need to be staked. Wash spider mites off with regular, strong hosings or control with soap spray. Remove spent flowers regularly to encourage more blooms.
Marigolds form the backbone of many plantings because of their diversity and adaptability. Use them freely in beds, borders, edges, pots, and boxes. Disguise dying bulb foliage with marigolds, or fill gaps left by discarded spring-blooming annuals and biennials. They also make long-lasting cut flowers, excellent for informal arrangements.