Few annuals are as dependably cheerful as marigolds (Tagetes patula). Easy to grow and long-blooming, these reliable plants start flowering in early summer and continue until frost if their old blooms are snipped. They also attract butterflies and hummingbirds into the garden. Marigolds grow best if watered deeply at least once a week.
Native from New Mexico south to Argentina, marigolds have been a staple in flower gardens for generations. Their height ranges from 6-inch miniatures to 4-foot bushes. These fragrant annuals are easy to grow from seed, but many gardeners buy started plants in garden centers in the spring. The flowers come in yellow, orange, red, cream and bicolored varieties. Small marigolds can be grown in pots or used for edging, while the taller varieties make good cut flowers.
Marigolds grow and flower best in full sun in moist, rich soil with good drainage. The plants tolerate light drought but flowering is diminished. If you're growing marigolds in pots, use a good-quality potting soil, not garden soil, which is too heavy and dense for good container gardening. Deadhead marigolds -- cut off their spent flowers -- to keep them blooming until frost and to improve their appearance. Fertilize them regularly, following the package directions for the proper amount to apply.
Watering New Plants
Water marigolds well immediately after planting them in the garden, both to settle the soil and to hydrate the roots. Keep the soil around the roots moist but not soggy until the plants are established. This usually takes 10 to 12 days.
Watering Established Plants
Established marigolds in garden beds need a good soak once each week. Give them enough water so that the soil is moist to a depth of 6 to 8 inches. If the weather is unusually hot or windy, they'll need extra water. Water marigolds in pots when the top 1 to 2 inches of soil is dry. If your marigolds stop flowering in hot weather, give them some extra water, which often restarts flower bud formation.
Applying fertilizer to the dry roots of any plant, including marigolds, makes the plant vulnerable to chemical burns from the fertilizer. Always water your plants well the day before you fertilize. This applies to any kind of fertilizer, including water-soluble ones.
Marie Roper began writing in 1987, preparing sales and training materials for Citadel, Inc. and then newsletters for Fullerton Garden Center. A trained horticulturist, she was a garden designer and adult-education teacher for the USDA Graduate School in Washington, D.C. Roper has a Bachelor of Arts in history from the University of Maryland.