Chrysanthemums were first cultivated in China as far back as the 15th century BC and more than 500 cultivars had been recorded by 1630. The genus consists of around 20 species of upright sometimes woody perennials from north and central Russia, China and Japan, and belong in the Asteraceae family. The flower heads range from 2.5cm to 30cm in size and come in yellow, white, pink, purple and red, making them versatile for planting schemes and cut-flower displays.
Florists’ chrysanthemums are grown for exhibition, the garden and cutting, and are often characterised according to their flower head form, flowering season and whether they are disbudded or non-disbudded. Disbudded chrysanthemums have all their flower buds on each shoot removed except for the terminal bud to increase the size of the remaining bloom. Non-disbudded chrysanthemums produce flower heads freely in a spray.
Pot chrysanthemums are grown commercially on a large scale and used as house or conservatory plants treated as short-term pot plants. Most are late-flowering cultivars brought into bloom by manipulating day length and temperature, and are sold in potting compost with enough nutrients to sustain flowering over a long period of time.
Rubellum Group chrysanthemums are clump-forming bushy perennials and are all named selections or hybrids of C. zawadskii. They have pinnatisect leaves and bear single, semi-double or double yellow-centred flower heads in a range of colours. Good for herbaceous borders as well as for cutting, they bloom in late summer/early autumn.
Early-flowering and midseason florists’ chrysanthemums are grown outdoors and do best in a sheltered site with full sun and a neutral to slightly acid soil type. Growing tips can be pinched out when the plant reaches 15-20cm to encourage early-flowering laterals.
Chrysanthemums grow to between 22cm and 1.2m high and should be staked at planting. Plants can be left outside over winter in areas that have only light frosts but otherwise will need to be lifted and stored over winter. Flowered stems need to be cut back to 15-23cm in mid to late autumn.
Summer-flowering varieties are easy to grow and provide a showy display for bedding or edging schemes. They bear many flowers and have a long flowering season. They can also be grown in pots or containers on a patio and the autumn varieties provide colour when most other bedding plants have finished.
Flower heads take on many different forms. Incurved varieties bear fully double spherical flower heads with ray florets opening from the base and curving upwards. More than 140 varieties have been awarded the Award of Garden Merit (AGM).
Being susceptible to many pests and diseases, chrysanthemums should be routinely treated with chemicals to prevent powdery mildew, rust, red spider mite, aphid and white fly. They may also be affected by leaf miner and capsid.
What the specialists say
Martyn Flint, Chrysanthemums Direct, Cheshire
"We sell most spray, early-flowering varieties that flower from September on the garden or allotment and are good for cut flowers. That is closely followed by the bloom varieties. Incurve varieties are always popular.
"We have been trying to bring back old varieties that people remember from the 1950s and earlier. ‘Blanche Poitevene’ from 1921 is one. It’s not very tall at 2.5-3ft and you can get 50-60 flowers if you pick it out a couple of times. It’s pure white and quite spectacular. We were often asked for it and we managed to get stock this year.
"One we’re trying to re-introduce is ‘Salmon Shoesmith’, which has bright colours like orange and purple and is one we’re often asked for."
Dave and Sue Hall, Halls of Heddon, Newcastle upon Tyne
"Our most popular variety is an incurving chrysanthemum called ‘Max Riley’. We find it to be very weatherproof so will grow quite happily outside and still produce good-quality blooms, unlike some of the top exhibition varieties that do better with overhead protection.
"The garden sprays are also very popular as a late summer/early autumn plant for borders. These also have a good following for showing as well, though most are looking to these for cutting. The single/open centred varieties are excellent for attracting pollinating insects. Popular varieties are ‘Enbee Wedding’ and its various sports.
"There has also been revived interest in hardy chrysanthemums — the Korean and Rubellum types — which are perfectly okay left outside as long as the soil is well-drained. These are a useful addition for herbaceous and mixed borders.
"We have rediscovered the old variety ‘Chatsworth’, a lovely bright-orange bronze, which we had lost. A chance conversation with a customer who had dealt with us for many years resulted in him sending us some cuttings. We used to grow more than 10,000 of this variety annually just for cut-flower and bunching markets but programmed all-year-round production of spray chrysanthemums has decimated the market for this traditional natural season autumn cut-flower crop.
"Other varieties of these hardier types that sell well are ‘Ruby Rayner’, ‘Grandchild’ and ‘Ruby Mound’. Generally, as the marketplace changes and the showing of exhibition chrysanthemums, which require an awful lot of dedication and time, has declined over the past 10 years, we are noticing a big swing away from the high-pedigree exhibition varieties to more easily grown cut flower and garden types."
Laura Oakes, Woolmans Plants, Spalding, Lincolnshire
"Traditional top-selling varieties at Woolmans tend to be early, outdoor flowering varieties. Typically the bloom varieties come top year after year. However, over the past few years we’ve seen an increase in demand for the spray types such as those from the Margaret, Pennine and Gompie series.
"We believe this is due to their ease of growth and maintenance, the increase in popularity of growing your own cut flowers, plus the fact that they are so reliable, providing at least a couple months’ worth of flowers for the garden.
"For the last two seasons we have introduced new indoor flowering varieties, bred by specialist hybridist John Nevill and brought into the range to appeal to the show grower. These have proven very successful and this shows that there is still some demand for the show-type blooms.
"Plans for any 2015 introductions are yet to be announced but we anticipate the introduction of further new varieties in the next few years."
Chris Day, Buckingham Nurseries & Garden Centre
"We do a limited range of blooms and sprays in late spring and early summer but that’s a declining market for us. But on the herbaceous side sales are increasing with the good summers and because people get good value from chrysanthemums.
"The traditional growing for individual blooms has less interest now, but the more informal way of growing has risen in the past five or six years.
"Chrysanthemum balls have definitely increased sales, aimed at the autumn bedding market, especially with the promotions we do with them now. We used to use a Dutch source but now we use a local grower in Leighton Buzzard called Rushmere Nurseries.
"People are now using chrysanthemums in a more integrated and less structured way than just in straight rows or pots. Double whites have been good and ‘Silver Princess’ and ‘Snowcup’ have done well too. Because chrysanthemums are now being offered all year round, people are using them more as temporary or replacement plants rather than long-term plants in the border, with bedding making it possible to do that cheaply if you deadhead."
Species and varieties
C. ‘Emperor of China’ is a Rubellum Group chrysanthemum bearing double silvery pink flower heads that are 25cm across with quilled petals. The leaves become red-tinged when flowering in late summer and early autumn. Height: 1.2m. Spread: 60cm.
C. ‘Enbee Wedding’ AGM (H3) is a spray florists’ variety with single light-pink flower heads up to 8cm across borne in early autumn. Height: 1.2m. Spread: 75cm.
C. ‘Mary Stoker’ is a Rubellum Group chrysanthemum with single rose-tinted apricot/yellow flower heads 5cm across in late summer and early autumn. The centres turn from green to yellow as the disc florets open. Height: 75cm. Spread: 60cm.
C. ‘Max Riley’ AGM is a fully recurved florists’ chrysanthemum with 12cm yellow flower heads when disbudded in early autumn. Height: 1.3m. Spread: 75cm.
C. ‘Mrs Jessie Cooper’ AGM is a Rubellum Group chrysanthemum producing semi-double red flower heads 9-10cm across in late summer and early autumn. Height: 75cm. Spread: 60cm.
C. ‘Pennine Oriel’ AGM (H3) is a spray florists’ chrysanthemum bearing anemone-centred cream flower heads 9cm across with yellow centres in early autumn. Height: 1.2cm. Spread: 60-75cm.
C. ‘Primrose Chessington’ is an intermediate to tightly incurved florists’ chrysanthemum producing primrose yellow flower heads that are 18-20cm across when disbudded in early autumn. Height: 2.2m. Spread: 75cm.
C. ‘William Florentine’ is an incurved florists’ chrysanthemum with pink flower heads 18cm across when disbudded in late autumn. Height: 1.6m. Spread: 45cm.
C. ‘Woolman’s Glory’ is a single florists’ chrysanthemum with large bronze flower heads 21cm across in late autumn. Height: 1.3m. Spread: 1m — when disbudded to four-to-six flower heads.