Calendula (Calendula officinalis) is a short-lived perennial in warmer climates, but it is usually grown as an annual flower in garden beds and containers. Although commonly known as pot marigold, calendula is different from the common marigold (Tagetes spp.). It is, however, part of the same Asteraceae family, along with daisies and chrysanthemums, and has a daisy-like appearance. It is planted in spring after the last frost and grows relatively quickly, flowering six to eight weeks from seeding.
The common name of pot marigold originated from the gold flowers that bloomed during the festivals of the Virgin Mary in Renaissance times (mary + gold = marigold). Traditionally, people often used the flowers in cooking. Today, gardeners grow these plants for their cheery flowers and profuse blooming habit. Though they most commonly are seen in varieties with yellow and orange flowers, you can also find them in subtle shades of pink and cream.
|Botanical Name||Calendula officinalis|
|Common Name||Calendula, pot marigold, common marigold|
|Plant Type||Herbaceous perennial flower, usually grown as an annual|
|Mature Size||1 to 2 feet tall and wide|
|Sun Exposure||Full sun to part shade|
|Soil Type||Average, well-drained soil rich in organic material|
|Soil pH||Neutral (6.0 to 7.0)|
|Bloom Time||May to early fall; will rebloom constantly if old blooms are dead-headed|
|Flower Color||Yellow, orange, cream, pink|
|Hardiness Zones||Perennial in zones 9 to 11 (USDA)|
Calendula is easy to grow from seeds directly sown in the garden or containers. Plant seeds in early spring and repot or transplant sturdy seedlings after the threat of frost. Calendula will tolerate poor conditions but grows best when it has rich soil. Once established, it doesn't need much water or fertilizer to grow. Calendula is a full sun plant, however, it's not a fan of sweltering hot temperatures and might start wilting in intense heat.
Calendula has no serious insect or disease problems. They can sometimes be susceptible to powdery mildew (remedied by good air circulation), and slugs and snails may feed on them, especially young plants. Keep ground areas clear of debris to minimize slug and snail damage. Aphids and whiteflies can sometimes be a problem; spraying with water or treating with insecticidal soaps can control these pests.
Calendula generally prefers full sun, but it sometimes languishes during the hottest months unless it receives some afternoon shade in hotter areas.
Like most members of the daisy family, calendula needs a well-drained soil high in organic material. Dense, wet soils can cause the roots to rot. This plant tolerates a wide range of soil pH but prefers a slightly acidic to neutral soil.
Water frequently until the plants are established. Mature plants thrive on only occasional watering. Avoid too much water with these plants.
Temperature and Humidity
Calendula prefers mild summer temperatures and may die away by the end of summer in very hot climates.
Calendula does not need much in the way of feeding. If planted in fertile garden soil, it requires no additional feeding at all. Marginal soils may require feeding with a balanced, water-soluble fertilizer, but over-feeding can make the plants leggy and spindly. Container plants require monthly feeding with a diluted, balanced fertilizer.
- 'Pink Surprise': Ruffled gold and yellow flowers, sometimes with pink edges and dark apricot centers
- 'Touch of Red': Flowers with a mixture of orange and red shades with red-tipped petals
- 'Greenheart Orange': Flowers with orange petals surrounding lime-green centers; a very unusual looking plant
- 'Citrus Cocktail': A compact, short plant with yellow and orange flowers; works well in containers
- 'Dwarf Gem': A compact variety with double-petal blooms of orange, yellow, and apricot; another good variety for containers
Although some people find the taste somewhat bitter, the flowers and leaves of calendula can be used in salads and other recipes, either fresh or dried. Calendula is also a medicinal herb that has been used in topical ointments for cuts and scrapes.
Collect calendula flowers in the late morning, after the dew has dried. Pick flowers when they are fully open, and often check because they come and go quickly. To dry the flowers, spread out the cut flower heads on a screen in a dry, shady spot. Turn them occasionally until they are papery dry, then store them in canning jars until ready to use.
Pinching back young plants will promote more compact, bushy growth and prevent the plants from becoming leggy. Then, deadhead the old flowers to encourage reblooming.
Calendula is very easy to grow from seeds or transplants. You should plant purchased seedlings after the danger of frost has passed; you can sow seeds just before the last frost date in the spring.
How to Grow Calendula From Seed
Calendula is a short-lived perennial that is generally propagated from seeds, which easily germinate and sprout. Seeds collected from the flowers can be saved and replanted; the plants will also readily self-seed in the garden.
Start calendula seeds indoors in seed starter mix about six to eight weeks before the last frost date. Or, you can sow them directly into the garden just before the last spring frost date. Most plants bloom within two months of seeding. These plants very often self-seed in the garden; don't mistake the seedlings for weeds.
Potting and Repotting Calendula
Although the "pot" in the common name "pot marigold" refers to this plant's traditional use in cooking, calendula is also commonly planted in pots, where it thrives. Most varieties grow well in containers, particularly shorter cultivars. Use any well-draining, organic potting soil, or make a mixture with a blend of half garden soil and half compost. Make sure the pot has plenty of drainage holes since this plant does not like to be soggy. Potted specimens need regular feeding with a balanced fertilizer.
Calendula is primarily an annual unless you live in the 9 through 11 hardiness zones. A hard freeze will kill the plants, but if you expect some frost for a day or so, you can protect the plants with a frost blanket overnight and uncover as the sun warms up the air the next day. Three to four inches of mulch will also protect the plants.