Common Name: Pot Marigold

General Information

Calendula officinalis is an erect or prostrate, much-branched annual plant with a deeply penetrating taproot; it can grow 40 - 70cm tall. The plant occasionally perennates[, ].
Pot marigold is commonly used in modern herbalism and is also used as a food, flavouring and source of materials. It is often cultivated on a domestic scale and also commercially for medicinal use. A very ornamental plant, it is often grown in the flower garden where it helps to repel insects[].

Known Hazards

None known

Botanical References

Range

Not known in the wild, the plant probably originated in the Mediterranean region

Habitat

The original habitat is obscure but it is found as a garden escape on waste, cultivated and arable land and along roadsides[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Annual
Height	0.60 m
Pollinators	Bees
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

Calendula officinalis originated in the Mediterranean region and can be grown as a summer annual in most parts of the temperate zone. It grows best in areas where annual daytime temperatures are within the range 16 - 26°c, but can tolerate 8 - 30°c[]. It prefers a mean annual rainfall in the range 500 - 800mm, but tolerates 300 - 2,500mm[].
An easily grown plant, it succeeds in any well-drained soil[, ], though it prefers a good loam and requires a sunny or at least partially sunny position[, , , ]. Plants flower best when they are grown in a poor soil[]. Prefers a pH in the range 5.5 - 7, tolerating 4.5 - 8.3[].
There are some named varieties[]. When well-sited the plant usually self-sows freely and will maintain itself if allowed[, ].
The flowers are sensitive to variations in temperature and dampness, closing when it is dark and when rain is expected[, ].
Average yield of the dry petals is 200 - 300 kilos per hectare, while yields of the complete inflorence may be 500 - 800 kilos[].
All parts of the plant are pungently scented[].

Edible Uses

Leaves - raw[, ]. When eaten they first of all impart a viscid sweetness, followed by a strong penetrating taste of a saline nature[]. They are very rich in vitamins and minerals and are similar to Taraxacum officinale (Dandelion) in nutritional value[].

Fresh petals are chopped and added to salads[]. The dried petals have a more concentrated flavour and are used as a seasoning in soups, cakes etc[]. High in vitamins A and C[].

An edible yellow dye is obtained from the petals[]. A saffron substitute[], it is used to colour and flavour rice, soups etc[, , , ]. It is also used as a hair rinse, adding golden tints to brown or auburn hair[].

A tea is made from the petals and flowers, that made from the petals is less bitter[].

There is no record of the seed being edible, but it contains up to 37% protein and 46% oil[].

Medicinal

Pot marigold is one of the best known and versatile herbs in Western herbal medicine and is also a popular domestic remedy[, ]. It is, above all, a remedy for skin problems and is applied externally to bites and stings, sprains, wounds, sore eyes, varicose veins etc[, ]. It is also a cleansing and detoxifying herb and is taken internally in treating fevers and chronic infections[, ]. Only the common deep-orange flowered variety is considered to be of medicinal value[].

The whole plant, but especially the flowers and the leaves, is antiphlogistic, antiseptic, antispasmodic, aperient, astringent, cholagogue, diaphoretic, emmenagogue, skin, stimulant and vulnerary[, , , , , , ]. The leaves can be used fresh or dried, they are best harvested in the morning of a fine sunny day just after the dew has dried from them[]. The flowers are also used fresh or dried, for drying they are harvested when fully open and need to be dried quickly in the shade[].

A tea of the petals tones up the circulation and, taken regularly, can ease varicose veins[].

An application of the crushed stems to corns and warts will soon render them easily removable[].

The leaves, blossoms and buds are used to make a homeopathic remedy[]. It is used internally in order to speed the healing of wounds[].

Agroforestry Uses:

The growing plant acts as an insect deterrent[], it reduces the soil eelworm population[].
The growing plant attracts hoverflies to the garden, the young of which are fairly efficient eaters of aphids[, ]. The flowers are attractive to bees[]. Marigolds are good companion plants, they grow well with tomatoes[].
Cucumber mosaic disease and powdery mildew can cause problems with this plant[].

Other Uses

The flowers are used cosmetically. They can be used in skin lotions and when added to hair shampoos will lighten the hair colour[].

The flowers are an alternative ingredient of 'Quick Return' compost activator[]. This is a dried and powdered mixture of several herbs that can be added to a compost heap in order to speed up bacterial activity and thus shorten the time needed to make the compost[].

A yellow dye is obtained from the boiled flowers[, , ].

The seed contains 40-46% oil of which 50-55% is highly conjugated calendic acid and 28-30% is the
non-conjugated linoenic acid. The oil could have applications in the manufacture of paints and coatings, cosmetics and some industrial nylon products[]. Yields of 0.38 tonnes per hectare have been achieved in Britain, and it is believed that this could be increased to 0.6 tonnes[].

An essential oil is obtained from the plant[]. It is used rather sparingly, in view of the difficulty in obtaining it, in perfumes that have a rather sharp tang[].

The flowers close when wet weather is likely to occur and they can therefore be used as a rough means of weather forecasting[].

Propagation

Seed - sow in situ from spring to early summer and again in September. The seed germinates best in darkness and usually within 1 - 2 weeks at 21°c[]. The plant often self-sows freely.