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 Asteracea family, along with daisies and chrysanthemums, with whom it shared the same daisy-like flower appearance.
The common name of pot marigold derives because the gold flowers that bloomed during the festivals of the Virgin Mary in Renaissance times (mary + gold = marigold) were often used in cooking. Today, gardeners simply grow these plants for their cheery flowers and profuse blooming habit. Though they most commonly are seen in varieties with yellow and orange flowers, there are also more subtle shades of pink and cream available. Calendula is commonly used in annual flower beds and in container gardening.
- Botanical Name: Calendula officinalis
- Common Name: Calendula, pot marigold, common marigold, Scotch marigold
- Plant Type: Herbaceous perennial flower, usually grown as an annual
- Mature Size: 1 to 2 feet in height with a similar spread
- Sun Exposure: Full sun to part shade
- Soil Type: Average, well-drained soil rich in organic material
- Soil pH: Prefers 6.0 to 7.0, but tolerates a wide range of soil pH
- Bloom Time: May to early fall; will rebloom constantly if old blooms are dead-headed
- Flower Color: Bright yellow to deep orange; creams and pinks also available.
- Hardiness Zones: 9 to 11, but usually planted as an annual in zones 2 to 11
- Native Area: Unknown; may be a garden creation, not a native species
How to Grow Calendula
Calendula is very easy to grow from seeds or transplants when placed in full sun and planted in ordinary fertile garden soil that is well drained. Purchased seedlings should be planted after danger of frost has passed; seeds can be sown just before the last frost date in the spring. Pinching back young plants will promote more compact, bushy growth and prevent the plants from becoming leggy. Deadhead the old flowers to encourage reblooming.
Calendula generally prefers full sun, but in hotter areas, it sometimes languishes during the hottest months unless it receives some afternoon shade.
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, but 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, and 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 do require monthly feeding with diluted balanced fertilizer.
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.
Varieties of Calendula
There are many varieties and cultivar series of calendula, offering flowers of slightly different appearances. Some popular ones include:
- 'Radio Extra' is a tall plant with bright orange, cactus-like blooms.
- 'Pink Surprise' has ruffled gold and yellow flowers, sometimes with pink edges and dark apricot centers.
- 'Touch of Red' has flowers with a mixture of orange and red shades with red-tipped petals.
- 'Neon' features double-petaled flowers in bold colors.
- 'Greenheart Orange' has flowers with orange petals surrounding lime-green centers; a very unusual looking plant.
- 'Tangerine Cream' has double-petaled flowers with bi-color blooms of bright orange and cream.
- 'Bronzed Beauty' has cream and peach flowers that grow on tall stems.
- 'Citrus Cocktail' is a compact, short plant with yellow and orange flowers; it works well in containers.
- 'Sherbet Fizz' has buff-colored flowers with deep red undersides petal tips.
- 'Dwarf Gem' is a compact variety with double-petal blooms of orange, yellow. and apricot; another good variety for containers.
- 'Fruit Twist' is a variety featuring a mix of single, double, and semi-double flowers in yellow and orange.
Although some people find the taste somewhat bitter, the flowers and leaves of calendula can be used in salads and other recipes, both fresh or in dried form. The plant sometimes regarded as a medicinal herb, and 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 check often because they come and go quickly. To dry the flowers, spread the cut flower heads out 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.
Growing From Seed
Start calendula seeds indoors in seed starter mix about 6 to 8 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 2 months of seeding. These plants very often self-seed in the garden; learn what the seedlings look like so you don't mistake them for weeds.
Growing in Containers
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 do well in pots, although shorter cultivars may be better suited. Use any well-draining, organic potting soil; or you can make your own 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 will need regular feeding with a balanced fertilizer.
Common Pests and Diseases
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 eliminate them.