Chrysanthemums: history, varieties and care, from All Saints' Day to all year round

Daniel Platteau

At the end of October, garden centres fill up with yellow, bronze, white and purple balls. In Belgium, as in France, the chrysanthemum is first and foremost the flower of All Saints' Day, the one placed on graves. That is selling it short. Grown in China for more than three thousand years and the emblem of the emperor in Japan, it comes in thousands of varieties, some of which return to the garden every autumn with no care at all. And thanks to a quirk of its flowering, you can find it in bloom twelve months a year.

In short: the All Saints' pot is often not very hardy; treat it as a long-lasting bouquet, or try to keep it frost-free. For chrysanthemums that come back every year, plant hardy garden varieties in spring (Rubellum group, 'Clara Curtis', 'Mary Stoker'…) in full sun, in soil that does not stay waterlogged. Pinch the stems until midsummer for denser clumps. Note that the plant is toxic to dogs and cats.

The chrysanthemum in brief

The chrysanthemum belongs to the large daisy family, the Asteraceae, like the ox-eye daisy, the aster and the sunflower. What we call a "flower" is in fact a flower head: hundreds of tiny florets packed onto a single receptacle. In double forms, almost all of them have taken on the look of petals.

Its name comes from the Greek chrysos, gold, and anthemon, flower: the "golden flower", a reference to the original yellow chrysanthemums. The genus Chrysanthemum now has 43 accepted species according to Kew's database, almost all from East Asia. But florists' and garden-centre chrysanthemums are nearly all hybrids grouped under the name Chrysanthemum × morifolium (also seen as C. × grandiflorum), derived mainly from C. indicum, a small yellow-flowered wild Chinese species, crossed with others.

Three thousand years of history

In China, a medicinal herb that became the scholar's flower

Chinese tradition dates its cultivation, as a medicinal herb, to the 15th century BCE, a date that is hard to establish with certainty. It then became a flower of ornament and poetry: the poet Tao Yuanming (4th-5th century), who grew it by his fence, made it the symbol of the scholar withdrawn from the world. More than 500 varieties were described in China by 1630. Today there are said to be more than 20,000 worldwide, about 7,000 of them in China.

In Japan, the emperor's emblem

Arriving from China around the 5th century, the chrysanthemum (kiku) took on a unique place in Japan. In the 12th century, Emperor Go-Toba made it the emblem of the imperial family; a sixteen-petalled chrysanthemum officially became the emperor's seal in 1869, and the Japanese monarchy is still called the "Chrysanthemum Throne". The Chrysanthemum Festival (Kiku no sekku), on the 9th day of the 9th month, dates back, according to tradition, to a first chrysanthemum celebration at the imperial court in 910. Autumn shows still draw tens of thousands of visitors in Tokyo.

In Europe, a sea captain from Marseille

Chrysanthemums reached the Netherlands around 1688, without lasting success. The real introduction came in 1789: sea captain Pierre-Louis Blancard brought a large-flowered C. morifolium from China to Marseille, the first seen in Europe. It flowered in England in 1796, the first English show took place in Norwich in 1843, and an amateur society founded in 1846 would become Britain's National Chrysanthemum Society. That same year, the botanist Robert Fortune brought back from China the "Chusan Daisy", ancestor of the pompon chrysanthemums (the name is said to come from the pompom on French sailors' caps). Earlier-flowering, they made outdoor cultivation possible in our climate.

Why All Saints' Day?

The link with cemeteries is recent: just over a century old. For the first anniversary of the Armistice, on 11 November 1919, French President Raymond Poincaré asked for war memorials and graves to be decorated with flowers. The chrysanthemum won out for very practical reasons: it is in full bloom at that time, it tolerates cold and it lasts. The habit soon crossed the border; according to the Belgian broadcaster RTBF, Belgians, who mostly placed candles on graves, then switched to flowers. The tradition later became attached to All Saints' Day (1 November, a public holiday in Belgium) and All Souls' Day (2 November).

As a result, in Belgium, France or Italy, you do not give chrysanthemums to a host. In the United States, on the other hand, the "mum" is the cheerful autumn flower placed by the front door, and in Australia it is given on Mother's Day.

Belgium, chrysanthemum country

It is little known, but Belgium is a major player in potted chrysanthemums. The family firm Gediflora, founded by Georges Pieters in West Flanders, breeds the ball-shaped chrysanthemums known worldwide as Belgian Mums, and exports its cuttings to every continent (95 million chrysanthemums, according to the company). Markets do not all follow the same calendar: November in Belgium, August in Scandinavia, September in the United States, early October in China for the national holiday.

Chrysanthemums all year round: the secret is the length of the night

The chrysanthemum is a short-day plant. More precisely, it is the length of the night that triggers flowering. For classic autumn varieties, the threshold is around 13.5 hours of daylight, a little more or less depending on the variety: above it, the plant grows leaves; below it, it forms buds. In Belgium, this threshold is crossed at the end of August; allowing time for the buds to develop, that gives flowering from late September to November.

Growers have used this mechanism for decades:

• To delay flowering, they switch on lamps in the middle of the night for two to three hours: the plant "thinks" the days are still long.
• To bring it forward, they draw blackout screens over the crops to impose 10 to 11 hours of total darkness every day, in high summer.
• From the start of this treatment to flowering, a potted chrysanthemum takes about 9 to 11 weeks.

This is how the chrysanthemum became one of the best-selling cut flowers in the world, available in every season at the florist's: in the 1990s, Japan sold about 2 billion stems a year and the Netherlands 800 million. "Spray" chrysanthemums with many small flowers, often anonymous in bouquets, make up the bulk.

A "chrysanthemum" for every season

In the garden, you can also play on diversity by counting the former members of the family. Until the 20th century, the genus Chrysanthemum also included the ox-eye daisy, pyrethrum and the corn marigold. Botanists have since moved them into other genera (Leucanthemum, Tanacetum, Glebionis, Argyranthemum…), but many keep their old name in everyday language.

Flower forms

Britain's National Chrysanthemum Society classifies flowers into thirteen groups. The main ones, those you will recognise in garden centres:

• Single: a visible yellow centre surrounded by one or more rows of petals, like a daisy.
• Anemone: a domed centre of small tubular florets, surrounded by flat petals.
• Pompon: small, tight, perfectly round balls.
• Incurved: a large ball whose petals curve in towards the centre, the classic show form.
• Reflexed: petals falling outwards, like a feather duster.
• Spider: long, thin, tubular petals, often hooked at the tip.
• Spoon: tubular petals that widen into a little spoon at the end.

The ball-shaped All Saints' chrysanthemums and "Belgian Mums" are compact plants covered in small flowers, bred to form an even dome on their own, without pruning.

Varieties worth knowing for the garden

These are the ones that deserve a lasting place in a border. They flower when almost everything else has finished, and bees and hoverflies visit them readily, especially the single forms whose centre is accessible.

These varieties are mostly found at specialist perennial nurseries, and in spring rather than autumn. The chrysanthemums sold in flower at the end of October in garden centres or supermarkets are rarely reliable hardy perennials.

Planting and growing a garden chrysanthemum

• When: in spring, after the last frosts (mid-May in Belgium). A plant set out in summer has time to root before winter; one planted in November much less so.
• Where: in full sun, sheltered from the wind. Chrysanthemums need light to flower well.
• Soil: ordinary garden soil, fairly rich and above all well drained. Standing winter wet, far more than cold, is what kills chrysanthemums in Belgium.
• Spacing: 30 to 45 cm between plants; stake tall varieties.
• Watering: regular during growth, without waterlogging. In pots, never let the root ball dry out completely.
• Feeding: a good mulch of compost is enough in the ground. In pots, a liquid feed during growth, then a high-potash feed (tomato-type fertiliser) when the buds appear.

Pinching: the trick for handsome clumps

When the plant reaches about twenty centimetres, in early summer, pinch out the tip of the main stem between thumb and forefinger. The plant branches out. Pinch the young shoots again as they grow, until about mid-July for autumn flowering, no later: the autumn buds need time to form. You get a lower, sturdier clump with many more flowers.

Disbudding, for big blooms

Lovers of large flowers do the opposite: on large-flowered varieties, they remove the side buds and keep only the central bud, which gives a bigger flower. On spray varieties, it is the other way round: remove the central bud so that the others all open at the same size.

After All Saints' Day: what to do with the pot?

The question of the season. Three options, depending on your ambition.

1. Treat it as a long-lasting bouquet. That is what it is first and foremost. Kept outdoors somewhere cool and watered as soon as the surface of the compost dries, a pot bought in bud flowers for several weeks. Choose one with plenty of buds still closed rather than in full bloom.
2. Keep it sheltered until spring. After flowering, cut the stems back to about twenty centimetres and bring the pot into a cold but frost-free place (a light garage, an unheated conservatory), keeping the compost barely moist. In spring, when it starts growing again, divide the clump or take cuttings, then plant out in the garden after the frosts.
3. Plant it in the ground straight away. It is a gamble: many ball chrysanthemums are bred for pot growing, not for hardiness. Your best chance: a sunny spot, very free-draining soil, a thick mulch over the crown, and leaving the dead stems until spring (they protect the heart).

On a grave, finally, a potted chrysanthemum suffers mostly from lack of water: a pot sitting on stone dries out quickly, even in November.

Overwintering garden chrysanthemums

Hardy varieties overwinter in the ground in most Belgian gardens. After flowering, leave the stems in place until late winter, or cut them back to about twenty centimetres, and mulch the crown with at least 5 cm. The RHS says most garden chrysanthemums tolerate about -5 °C without protection; beyond that, and especially in heavy, wet soil, the risk rises.

For precious or doubtful varieties, the classic collectors' method is to lift the stools after flowering: cut back to 20 cm, shake off the soil, remove the leaves, then stand the stools in a tray on a few centimetres of barely moist compost, in a cold, frost-free place. They start growing again in late winter and provide the spring cuttings.

General advice on protecting the garden from the cold is in our article Overwintering garden plants (in French).

Propagating: cuttings and division

• Cuttings: in spring, take shoots 5 to 7 cm long from the base of the clump, remove the lower leaves and insert them in a mix of compost and sand or fine grit. At 10 °C or more, in bright light out of direct sun, they root in about three weeks. This is the surest way to keep a variety: grown from seed, garden varieties do not come true to the parent plant (only a few varieties are sold as seed).
• Division: every two or three years, in spring as growth restarts, lift the clump and replant the outer pieces, which are more vigorous than the centre.

Possible problems

• Aphids on young shoots in spring, leaf miners (tunnels in the leaves), earwigs and capsid bugs damaging the buds, red spider mites in hot, dry weather. Damage is usually superficial: keep an eye out and remove affected parts.
• Slugs: they love young spring shoots.
• White rust: small pale spots on the upper side of leaves, whitish to pinkish pustules beneath. It is the most serious chrysanthemum disease and highly contagious; pull up and dispose of affected plants (not on the compost heap).
• Powdery mildew in dry weather, grey mould in wet weather: keep clumps airy and avoid wetting the foliage.

True or false: a few misconceptions

"Chrysanthemums purify the air in your home." Mostly false. The idea comes from a 1989 NASA study carried out in small sealed chambers. A 2019 analysis calculated that it would take 10 to 1,000 plants per square metre to match the air exchange provided by normal ventilation. A chrysanthemum decorates; it does not measurably clean a room.

"Chrysanthemums are toxic to animals." True. The ASPCA Animal Poison Control Center classes them as toxic to dogs, cats and horses: they contain sesquiterpene lactones and pyrethrins, which can cause vomiting, diarrhoea, drooling, loss of coordination and skin irritation. In humans, frequent handling can also cause contact dermatitis, a known problem among florists.

"Chrysanthemums are used as an insecticide." Partly true, but not the All Saints' kind. Insecticidal pyrethrins are extracted from the flowers of Dalmatian pyrethrum, Tanacetum cinerariifolium, once classed among the chrysanthemums.

"Chrysanthemums are edible." True in Asia. Tea made from C. morifolium flowers is common in China, and the leaves of edible chrysanthemum (Glebionis coronaria, Japanese shungiku) are eaten as a vegetable. Do not taste a garden-centre pot, though: it may have been treated.

Test yourself

Further reading

• Autumn asters: planting, care and choosing the right varieties, the other great autumn perennial.
• Japanese anemones (in French), for partly shaded spots.
• November in the garden, the month's jobs.

Sources

• ASPCA Animal Poison Control Center. (n.d.). Chrysanthemum. https://www.aspca.org/pet-care/aspca-poison-control/toxic-and-non-toxic-plants/chrysanthemum
• Cummings, B. E., & Waring, M. S. (2020). Potted plants do not improve indoor air quality: A review and analysis of reported VOC removal efficiencies. Journal of Exposure Science & Environmental Epidemiology, 30, 253–261. https://doi.org/10.1038/s41370-019-0175-9
• Focus on Belgium. (2020, 28 October). Belgium, large exporter of chrysanthemums. https://focusonbelgium.be/en/business/belgium-large-exporter-chrysanthemums
• Gediflora. (n.d.). Belgian Mums. https://www.gediflora.be/en
• Kawata, J. (n.d.). Year-round production of chrysanthemums in Japan. Japan Agricultural Research Quarterly, 4(2), 23–27. https://www.jircas.go.jp/sites/default/files/publication/jarq/04-2-023-027_0.pdf
• New York Botanical Garden. (n.d.). Are there any perennial varieties of fall mums? https://libanswers.nybg.org/faq/223436
• Ville de Paris. (2024, 18 October). L'étrange histoire du chrysanthème, fleur d'or des cimetières. https://www.paris.fr/pages/connaissez-vous-l-histoire-de-la-fleur-d-or-des-cimetieres-5220
• Royal Horticultural Society. (n.d.-a). Chrysanthemum 'Clara Curtis' (21d). https://www.rhs.org.uk/plants/124023/chrysanthemum-clara-curtis-21d/details
• Royal Horticultural Society. (n.d.-b). How to grow chrysanthemums. https://www.rhs.org.uk/plants/chrysanthemum/growing-guide
• Taylor, J. M. (2013, March). History and development of the modern chrysanthemum. Chrysanthemum (National Chrysanthemum Society). https://horthistoria.com/articles/articles_articles/articles_articles_history_of_the_modern_chrysanthemum/
• Wilquin, M. (2024, 28 October). Pourquoi fleurit-on les tombes de nos défunts ? RTBF. https://www.rtbf.be/article/pourquoi-fleurit-on-les-tombes-de-nos-defunts-11456066
• Wikipedia. (n.d.). Chrysanthemum. https://en.wikipedia.org/wiki/Chrysanthemum