The Gold Daisy, Calendula officinalis, sometimes known as the Pot Marigold has been widely grown since very ancient times. Calendula originated as a wild flower native to Southern Europe from Macaronesia (West Africa and associated islands) through the Mediterranean to Iran.
Soon its edible and valuable medicinal properties saw it cultivated throughout Greek, Roman, Middle Eastern and Indian Cultures. Later it spread throughout Europe then Asia and now it is a worldwide indispensable garden favourite.
The name Calendula comes from Latin (Roman) ‘kalendae’ meaning ‘first day of the month’ presumably in reference it the Calendula’s remarkable ability to flower every month of the ‘calendar’ year when grown in its native habitat. The common name Pot Marigold refers to the aromatically edible uses of Calendula for seasoning meat and vegetables classically cooked in a large pot. Marigold refers to the Virgin Mary i.e. ‘Mary’s gold’ and is associated with the bright golden ray petals surrounding a sunny yellow centre that became associated with the golden halo and radiance of the Virgin Mary and baby Jesus.
Calendula is a member of the Daisy Family, Asteraceae. There are up to 20 species from quite dwarf carpeting groundcovers hardly more than 12in./30cm at the most. While other species are bushy and robust and can easily reach 60cm/2ft and a few even top 80cm/32in. All feature aromatic, sometimes nearly sticky and softly hairy (bottom and top) lanceolate, oblong leaves with entire smooth or softly wavy margins. Leaves are classically a medium green with the distinctive spicy fragrance. A few select hybrids have much shorter leaves and some have a vivid yellow variegation stripped against the golden blooms.
Flowers in the wild species are often a single row of ray floret petals around a central disc of tightly packed smaller pollen-laden florets. Flowers range in size from 4-7cm/1.6-2.8in but hybrid varieties can be much larger. Famous hybrid Calendula ‘Pacific Beauty’ can often support blooms of 10-15cm/4-6inches across and sometimes larger. These can be fully double creating floral discs 2.5-5/1-2inches deep in closely packed, satin petals. Colours are all the classic sunset shades but can range from butter and cream to nearly white; every shade of yellow; glistening gold, orange, brick red, russet; plus many bi and tri-colour variations. Flower petals are usually flat, long and somewhat satiny or silky, but can also to inwardly or outwardly recurving, fluted or pinnate to create a spiked ‘star-burst’ effect. The very largest blooms are almost always double or semi-double. The hardiest, spreading varieties are often less semi-double or single reflecting their wild parentage.
Gardeners worldwide consider Calendula to be one of the easiest, hardiest, most reliable and highly versatile of all garden plants. It is technically an aromatic tender perennial. But due to its resilience to climatic extremes and soils, Calendulas are often grown as bedding Annuals. They are frequently grown in cold climates as a Summer and Autumn flowering Herb. While in mild and moderate climates, they are a favourite for the cool season and especially Winter through Early Spring colour.
Calendula seed is hard and unusually hook shaped; often with additional barbs. It is believed that once, long ago in its wild origins, this hooked quality allowed the seed to be snagged by the fur and hair of passing animals then later in the clothing of Gardeners and Passers-by. Once snagged the seed had a free ride and was inadvertently carried on from place-to-place. It apparently was so effective that Calendulas have now spread around the world to flourish in all continents other than the Polar regions.
The seed of Calendula is extremely easy to germinate. Seed can be sown almost any time provided conditions remain moderately mild and moist. Under ideal conditions, germination happens within 6-14 days. This is when the growing site remains airy, bright but damp and temperatures range between 59-68F/15-20C. Seed will germinate up to 29.45C/85F but above that seed and plants often fail and wither or certainly at least stop flowering. In colder temperatures, Calendula seed will still germinate but more slowly and the sowing site must be sunny and free-draining. Seed will often fail in cold, shaded, wet environments.
Small seedlings are somewhat more vulnerable to cold than advanced and mature plants. Calendula can usually withstand freezing down to 25F/-3.9C without much damage. Advanced plants often withstand considerably more cold provided this is brief. But persistent wintry weather accompanied by cloudy, icy or constantly cold and wet conditions will see them slowly collapse. They are famous for withstanding cold or freezing in low-humidity ‘dry’ climates and bouncing back quickly with no apparent signs of damage. Even when top growth is singed or killed by freezing, these damaged leaves quickly soften and meld together; then dry and crust over to create a canopy which will protect the leafy interior. Once all danger of frost has passed, the internal leaves and stems, burst through this protective crust and the Calendula quickly spreads out and upward into glorious flowering.
Because of its beauty, reliability and versatility plus its ease of growth and hardiness, Calendula is a favourite for school projects, children’s gardens and wherever an abundance of bright, low maintenance colour is desired over a long period. It is also a favourite in many Cottage Garden and Wildflower seed mixes.
In climates with mild Winters, especially Climate Zones 8-11, Calendula is a year-round garden plant, often planted or sown for the cool seasons from Autumn, Winter and Spring. Warmer (sub)tropical climates use it for hardy Late Autumn, Winter and Spring colour but find it withers in summery heat. In very sheltered corners of Zone 6-7, they can also be used for Autumn and Spring colour but will need protection and sheltering from severe freezing. In colder climates Calendulas are sown in Late Winter to Early Spring under glass or in a cold frame; then transplanted once all danger of frost has passed for used in the Summer and Autumn Garden.
Flowering from seed will begin in as little as 8-10 weeks when conditions remain ‘ideal’. This is usually the case when started in Late Summer or Autumn; and also when sown in Late Winter or Early Spring under glass or outdoors in Spring for Summer blooms. When sown in the cooler days of Autumn flowering can be delayed somewhat dependent upon the Winter weather they encounter.
Possibly their greatest and most spectacular performance is when they are sown from seed in Late Summer and Early to Mid Autumn. This way the seed germinates quickly and growth is rapid. The absolute ideal is to time the sowings so that plants mature to their first bud and bloom just as weather cools in Late Autumn to the first days of Winter. This way the plants are refrigerated in the cool air so grow slower. This produces robust and stocky growth with the formation of much larger buds and massive blooms often 10cm/4in or more across that are fully double and long lasting. This way, the plants providing welcome colour throughout Winter and Spring.
When planning the best growing position for Calendulas, choose a sunny site with enriched, well draining soil and plenty of water. They will grow in partial shade, but tend to flop or become somewhat spindly with soft growth that often splits away from the stem or collapses during heavy rain or wind. They grow in a variety of soils but they prefer pH 6-7 and respond to the addition of aged manure or mature compost.
In low pH ‘acid’ soils dust the ground liberally with Dolomite, Dolomag or Garden Lime and dig this in prior to planting or sowing. Calendula plants respond to a good slow-release balanced General Plant Food like 20-20-20 while young. As Calendula plants mature and buds begin to develop, switch to a fertiliser higher in Phosphate and Potassium (Potash) like 10-20-20 or 5-10-25 or similar basic ratio. This will encourage bigger buds and larger blooms that are more double and vibrant in colour. But even with no care or feeding at all, hardy Calendula varieties will often put on a valiant performance.
Seed germinates equally rapidly in the ground as in containers. Sow each seed about ¼ inch deep or just barely covered with moist earth. Once sown, maintain even soil moisture and moderate warmth combined with bright light or direct sunshine. Once seedlings emerge their growth is often rapid. The young plants can be either thinned in the bed or row, or transplanted after a few weeks to stand 20-30 cm/8-12inches apart. The distinct advantage to sowing into containers is control over climatic conditions and also the potential for eliminating predation by birds and insects. Since the ideal time to grow Calendulas to perfection is sowing in Late Summer and Early-Mid Autumn, it is best to sow in an airy, bright but partly shaded, cooler site which avoids extreme summery heat. Sow only a few seedlings in each container. This way each small plant has the opportunity to develop strongly without undue competition.
As the weather cools and the seedlings gain some size, move their containers or punnets into stronger or full sunlight. If seedlings begin to stretch and flop, pinch out their central growing tip once their internal growing stem reaches 3-5in/7.5-10cm. This will encourage branching and much stronger plants. Always move flopping or stretching Calendula seedlings into stronger sunlight without delay to maintain best plant health.
Seedlings should be hardened-off before transplanting into their final flowering positions. They can be transplanted once they reach 3-5in/7.5-10cm or larger. Calendulas are quite accommodating to cramped root conditions while young. So they can be grown-on in containers for several months without ruining or setting back their ultimate development. Just keep pinching them back so that they continue to become bushier rather than lanky and soft.
When transplanting, it is best to prepare the soil at least a few days in advance. While they are quite hardy to a variety of conditions, they respond well to extra attention and care. The plants are so hardy that they will usually survive an even brutally injurious transplant. But by far the best results occur when advanced and well-grown seedlings are carefully shifted from their growing containers into their final flowering position without any root damage or major disturbance. Water them into place immediately.
Choosing a cloudy and damp day, with further damp weather ahead further insures a smooth transplant transition. Watch these transplants carefully and be prepared to water immediately should weather become dry, hot and/or windy, resulting in wilting. Severe wilting can set back the plants and/or result in fewer fully double blooms.
Calendulas are both showy and also make aromatic and brightly appreciated cut flowers. The first blooms are by far the largest and those that follow are often nearly as large and very double. As plants mature and spread out, many more somewhat smaller and often less-double blooms follow. Dead-heading will keep plants in continuous bloom but leave a few of the best seed heads to collect or self-sow for the next crop.
Hybrid Calendula varieties often revert back to their wild form in successive generations. So for the finest quality exhibition blooms Calendula hybrids are best planted from fresh seed stock each season. Or use the gathered seed in the wildflower garden or broadcast between other Annuals and Perennials.
Once plant stems begin to spread and appear to have spent most of their best blooms cut the plants back by 1/3 or more to strong outward-facing buds. Remove any diseased, old and tatty foliage and stems. Lightly feed and mulch with additional aged compost or manure; water this in and the plants will often bounce back with a new lease-on-life.
Calendulas, especially the dwarf hybrids are excellent in container gardens and window boxes. They respond very well to feeding and cutting back to keep them shapely. The most spectacular taller hybrids are most dramatic and very successful when grown in larger containers, landscape planters, terraced beds and tubs. Their ultimate size requires a larger root area but their over-all performance is definitely worth the effort!
Calendulas are more than just pretty faces. Calendula officinalis has been widely used by Herbalists as clearly documented since the 12th Century but most assuredly for very much longer than that. Calendula is medically used today as in ancient times as an antifungal, antigenotoxic, anti-inflammatory, antiseptic, astringent anti-viral medication. Calendula extracts are used to reduce inflammation; sooth bruised and irritated tissue; aid healing; stop bleeding; plus heal and relieve radiation dermatitis. They are a classic remedy for relieving psoriasis and a variety of skin rashes as well as chapped lips and cracked, dry feet and hands. The extracts, especially when consumed as a soothing tea are said to relieve jaundice and have been used for many centuries to relieve abdominal cramps; constipation; muscle spasms, especially leading to cramping and even the symptoms of HIV!
Calendula flower petals and pollen contain triterpenoid esters plus Flavoxanthin (Flavonol); Oleanane, Sesquiterpene and Triterpene Glycosides; Saponins and Auroxanthin carotenoids. These are important antioxidants. Plus the carotenoids are an excellent source of the yellow-orange pigments used as a substitute for Saffron and produce a valuable dye for fabric and food plus cosmetic colouring. These dye agents are often used to colour cheese.
While the aromatic leaves and stems also contain carotenoids. These are different ones to those contained in the flowers, including mostly Lutein, up to 5 percent Zeaxanthin, and Beta-carotene. Plus Calendula plant extracts also contain aromatic essential oils, resins and Saponins which make them valuable in balms, cosmetics, anti-aging skin lotions, salves and soaps.
The essential oils from Calendula are frequently used in aromatherapy. These are considered to be refreshing, rejuvenating and extremely soothing. They are often inhaled as well as massaged into the skin for the healing medicinal qualities. Classically, in the Language of Flowers, Calendula is regarded as one of the ‘divine’ flowers and plants that bring joy and winning grace while it effortlessly overcomes grief, jealousy and trouble. Thus Calendula is a valuable herb worth generous planting throughout the garden.
It’s spicy, pungent foliage, flowers and buds are often used to season beef dishes giving rise to its other common name, “Pot Marigold”. The flower buds are especially beneficial to enhance the flavour of beef and roasts as well as in stews when allowed to simmer for an extended period. The pretty petals are edible, and enhance both the presentation and aromatic spicy flavour of salads.
Needless to say, the humble Calendula has been a devoted friend to Humankind since earliest antiquity. Yes, this lovely flowering herb is worth its weight in gold and that is possibly why it is affectionately known as The Golden Daisy.
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