Plants in the Calendula genus, and C. officinalis in particular, tick plenty of boxes. They can be sold as classic cottage garden plants, culinary and medicinal herbs, plants to please children, container specimens and border edging. Our increasingly forgiving climate encourages classic pot marigolds (C. officinalis) to flower through to the frosts — and some varieties now over-winter.
Those that won’t last through the cold season can be replaced by the mid-yellow flowers of C. ‘Wintersun’, which provides cheery winter colour against pretty, mid-green foliage.
Most people are more familiar with summer-flowering plant varieties and want to add instant colour, for which Calendula is a great plant. The current range of colours includes classic orange to yellow, cream, purple and even green.
C. officinalis plants have decorated English gardens for centuries as well as providing cheap and effective medicine. Some herbalists still regard it as a cure-all — sore tonsils, sunburned skin, ulcers, eczema and psoriasis are all said to be soothed by teas, potions and ointments made from the daisy-like flowers.
The plants make a colourful display, and many consider them prettier and more appropriate for English gardens than the exotic, blowsy African marigolds (Tagetes).
Most calendulas range in colour from pale yellow to deep orange, and the flower size varies. The genus includes annuals, some of which are beginning to behave like perennials in the warmer parts of the UK. They need well-drained fairly poor soil and they like a sunny site, although they can cope with a little shade.
In California, mildew is a major problem on Calendula, but this seems to be less of an issue in this country. Aphids, slugs and snails sometimes attack the plants and they can be dealt with in the normal ways.
Propagation is from seed in situ in spring. The “throw and grow” method works very well here.
In frost-prone areas, autumn sowing and frost protection is the best way to grow calendulas but, once they have been grown on a site they enjoy, they will self-seed with abandon. Rather like that other children’s favourite, nasturtiums, they will reappear year after year.
They key to keeping these plants looking good is to dead-head religiously until — or unless — you want them to set seed.
What the specialists say
Jekka McVicar, owner, Jekka’s Herb Farm, Gloucestershire
“C. officinalis is known as ‘pot marigold’ — not because it lives in a flower pot but because it used to often end up in a cooking pot.
“In other words, it was used as a vegetable — mostly the leaves. This was in medieval times and earlier, before the apothecaries started using it as a medicinal herb. It tastes fairly naff as a vegetable — I have known better-tasting ones.
“The C. officinalis Fiesta Gitana Group Award of Garden Merit has really attractive, low-growing flowers, very good for container growing — in barrels for instance, because the plants are only 15-20cm tall, so don’t grow as high as most bedding marigolds. The real tip is to make sure that, once in flower, you keep dead-heading or they will get woody and stop.
“They usually flower till the frosts set in — but mine have gone right through this year. They’re terribly easy to grow and wonderful for children. I thoroughly recommend them. The modern plants have a good range of colours with purples, blues and greens.”
Trevor Triggs, owner, Cross Common Nursery, Cornwall
“We tend to grow what other people don’t. We have to survive by being different in order to encourage people to come to the nursery.
“The field marigold, C. arvensis, grows well in salt winds and in coastal areas. It seems to have the type of leaf that is resilient to salt. If you look closely at the leaves they are more hairy than other varieties and are slightly silver-green in colour.
“Flowers tend to be larger than on most other calendulas and their colours range from orange to brown. They are not stable, and they do not come true from seed. Also, in this part of the world, the plant is compact — about 30-35cm. It needs very dry, free-draining soil to survive and it is well suited to surviving drought. If the plant gets too wet you will lose it and, in that respect, it’s like an Echium.
“I doubt most of these would survive in an ordinary bed, but here they survive as perennials. They’re unlikely to be killed by frost, but a damp climate can kill them.”
Andy Hart, planteria manager, Almondsbury Garden Centre, Somerset
“We sell Calendula from April until October, both in our herbaceous A-Z cate-gory and as a herb.
“Pot marigold is a good old English flower and so we get a lot of interest in it from that point of view.
“It’s important to give them space and put a good number on display. While they are in pots we have to keep a close eye on them. Too little watering and they crisp up quickly. Too much and they rot. It’s a matter of finding a happy medium.
“Once in the ground they’re fine and, although they like sun, they can take a little shade.”
Species and cultivars
• C. arvensis is a new plant, ideal for coastal and drought-stricken areas. The orange to brown blooms are larger than most and are set against slightly white-green foliage. Once established in milder areas it behaves as a perennial.
• C. officinalis Fiesta Gitana Group Award of Garden Merit is a compact dwarf variety of about 30cm. It features yellow to orange flowers and a neat habit, making it an ideal bedding or large container plant.
• C. officinalis ‘Orange King’ has a high resistance to mildew and double flowers.
• C. officinalis Pacific Beauty Series is another great cut flower, with plants growing up to 60cm in height and a mix of neat yellow or orange flowers, some with brown centres.
• C. officinalis ‘Lemon Queen’ carries chunky pale yellow flowers up to 45cm.
• C. officinalis ‘Porcupine’ is a newish plant with stunning spiky, orange petals.
• C. officinalis Prince Series ‘Indian Prince’ produces flowers with dark orange to red petals, and is great for cutting as it grows to about 75cm tall.
• C. ‘Wintersun’ is able to over-winter, just as the name implies. Its bushy habit and compact yellow flowers look great from late autumn to early spring, making it a good filler for window boxes. It needs to be sown in July to August.