Members of the Calendula genus that are grown in gardens are usually versatile hardy annuals (some wild species are perennials) that reach between 30 and 60 cm in height.
They carry daisy-like flowers of orange, red or yellow in color and bloom from spring through to Autumn, depending upon the species.
Calendula are known by the common names of Pot, English, or Field Marigold. They make a great bed, border, container or cottage garden plant.
Pot Marigold (Calendula officinalis) photograph by AudreyJM529.
They are an excellent companion plant in vegetable gardens as their leaves contain compounds that act to repel pests.
Calendula gets its common name Pot Marigold because the flowers are often used in pots when cooking soups and stews. It is used to add both colour and flavour to many dishes, and is also used in cheese making.
There are about twenty species in the Calendula genus. They are natives to the Middle East, Mediterranean Europe and nearby islands such as the Canaries and Azores.
Members can be either annual or perennial and they have an herbaceous nature.
Calendula typically have hairy leaves of between two to seven inches (5 to 18 cm) in length; these are arranged in spirals.
The Calandula flowers can be either ray or disc floret in nature and are in the range of 1 to 3 inches (3 to 8 cm) in diameter.
As a member of the daisy family Asteraceae (Compositae), Calendula are closely related to other commonly grown garden plants such as Tagetes, Dahlia, and Chrysanthemum.
Some of the best known members of the Calendula genus include:
If planning to grow Calendula outdoors from seed it is usual to sow seeds at a depth of ¼ inch (6mm) in the early spring.
In hot areas that do not get little winter frosts (e.g. zones 9 to 10 in the USA) it is best to sow seeds in the Autumn). In areas where summers are cool, it is also possible to sow pot marigold seeds in the Summer for Autumn blooming.
When starting off seedlings indoors it is best to start the preparations for growing Pot Marigolds about 8 weeks before planting out (usually after the last frost).
The germination process should be done in the dark and takes about one or two weeks at 70 degrees Fahrenheit (21C). Dwarf Calendula species should be planted about 8 inches (20cm) apart, whereas taller varieties should have a spacing of around 20 inches (50cm).
Pot and English Marigold should be grown in areas of bright sunlight in an ordinary soil of pH 5.5 to 7.
Young plants require to be pinched back to encourage bushiness. Deadhead plants to encourage prolonged blooming. Give an occasional feed. Water frequently, but ensure to avoid getting water on the leaves to prevent mildew.
Calendula officinalis (Pot Marigold, English Marigold)
Pot Marigolds are very versatile annual plants that are much loved by gardeners as they produce blooms throughout the year and are very easy to germinate from seeds.
They perform best in cooler climates, but by timing when the plants are sown (e.g. Sow in autumn in warmer climates) they can be grown in most areas, however they are not very tolerant of frosts.
Plants usually reach an height of between 12 and 30 inches (30 to 75 cm) depending upon variety, and should be sown at about 6 to 24 inches apart (15 to 60 cm).
They prefer to grow in sunny parts of the garden, but should be grown in lightly shaded areas in very hot areas. Soil can be ordinary and slightly acidic to neutral pH 5.5 to 7).
Growing Tip: By cutting the plants back before the heat of summer in hot areas, and providing plenty of water to the surrounding soil, it is often possible to get a second Autumn bloom from spring flowering pot marigolds.