Marigolds – The most common types of marigold are the wild marsh marigold, the tall African marigold, and the robust French marigold. African and French cultivars frequently are hybrid to sustain longer bloom and soften their pungent aroma. The resulting plant is called a triploid marigold, which is commonly called the mule marigold because of its poor ability to produce seeds.
Latin name for the common or marsh marigold is Calendula officinalis, christened as such because ancient Romans noticed that it bloomed on the first, or calends, of every month. Common but colorful, inexpensive and easy to germinate and grow, there are varieties available in a wide range of heights, hues and flower forms.
Pot marigold refers to the culinary use of this hardy annual. The species has cherry, single orange flowers and aromatic, light green leaves. 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. ‘Fiesta Gitana’ is a compact form, which has orange or yellow (sometimes bicolored) flowers. Marigolds have a long flowering period.
Use marigolds freely in beds, borders, edges, pots, and boxes. Marigolds are best used as a ‘companion plant’ to help protect other plants; however, marigolds do also have some mosquito repellent properties, so it’s a bit of an all-rounder. Marigolds contain a chemical compound called thiopenes in the roots. This plant repels aphids, cabbage maggots, white flies and many other pests. Marigolds are particularly good at protecting tomato plants.
Marigolds are so easy to grow. 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. Space the plants 8-16 inches apart depending on the variety.
French marigolds in summer container
Varieties of marigolds
Marigolds are categorized into three groups: French, African, Signet and triploid marigolds:
– The French marigolds are small bushy plants that are about 6-12 in (15-30 cm) in height. The flowers are up to 2 in (5 cm) across and are composed of a dense arrangement of “rays” that come in yellow, orange and a unique bronze color. The French marigolds bloom continuously until cut down by frost. French marigolds are ideal for edging flower beds and in mass plantings. They also do well in containers and window boxes.
– The African marigolds, also called American marigolds, are tall stout plants that grow to 3 ft (0.9 m) in height. They have larger blossoms and a shorter flowering period than their French cousins – remove faded flowers to encourage a second flush of bloom. African marigolds are excellent bedding plants. Tall varieties can be used as background plantings.
– The triploid marigolds are sterile hybrids obtained by crossing the French with the African species. These triploids are non-stop bloomers with impressive 3 in (7.6 cm) flower heads in clear warm colors of gold, yellow, red and russet.
– Signet marigolds are quite different from most marigolds. Signet marigold plants are bushy with fine, lacy foliage. The small, single flowers literally cover the plants in summer. Flower colors range from yellow to orange. They are also edible. The flowers of signet marigolds have a spicy tarragon flavor. The foliage has a pleasant lemon fragrance. Signet marigolds are excellent plants for edging beds and in window boxes.