Chrysanthemum Chrysanthemums inject a splash of colour into late summer and autumn borders, and come in a wide range of sizes, shapes and colours. They're often still going strong within weeks of Christmas, and outlast almost everything else in cold, wet conditions.

In this article

Recommended varieties Growing tips

Problem solver Where to see them

Chrysanthemums have a long history, but although the Chinese were growing them 2,500 years ago they didn't reach Europe until 1789. Pierre Louis Blancard brought the first plants back from the Far East, and by 1802 had raised ten cultivars. Today there are more than 650 varieties available from garden centres, with 77 holding the Award of Garden Merit from the Royal Horticultural Society.

The best types for late autumn border colour are those that grow in sprays. They produce a mass of smaller blooms that are less likely to rot in wet weather. The Koreans and Rubellum group provide some of the first cultivars to flower in late summer, and are probably the most dependable. They come in a diverse range of colours and shapes.

Anemone-centred spray chrysanthemums

They have slightly raised flower centres surrounded by a single rosette of petals (forget the name - they don't look like anemones!).

• C. 'Pennine Oriel': has cream-coloured flowers with yellow centres, but needs support since it can grow 1.2m (4ft) high. The Royal Horticultural Society has given it the Award of Garden Merit.

Other border chrysanthemums

• C. 'Duchess of Edinburgh': single red flowers with greenish-yellow centres. Tall and lax, it will need staking to keep it upright.
• C. 'Mei-kyo': its rich pink double flowers open from late summer to late autumn, given decent weather. Good for cutting, and, if picked early, will last a long time in water.
• A good alternative is the related 'Bronze Elegance' or, better still, the brilliant yellow 'Nantyderry Sunshine' which has a stiff, twiggy habit, smallish leaves and a mass of brilliant sunny flowers from late September onwards. 'Nantyderry Sunshine' has been given The Royal Horticultural Society's Award of Garden Merit.
• C. 'Ruby Mound': a good outdoor spray variety with small, double flowers in an unusual shade of red.
• C. 'Margaret': as the season advances, the choice of dependable outdoor spray types becomes more limited, but this dark pink keeps flowering into November. The Royal Horticultural Society has given it the Award of Garden Merit.
• C. 'Emperor of China': often flowers the latest of all, with silvery pink blooms in late autumn, set off by the leaves that turn beetroot red as they age.

Site and soil preferences

Plant the rooted cuttings or new divisions of border plants in spring as soon as the soil begins to warm up. They like average, free-draining soil in full sun. Cuttings raised in a greenhouse shouldn't be planted outside until the danger of frost has passed.

Keeping plants healthy

Plants develop into a healthy clump, known as a stool, which is easy to divide into smaller divisions, each with a single shoot and some roots. If you lift and divide your plants every third year, they'll retain their vigour and produce stocky stems that are easier to support. If you fail to lift and divide them, don't worry: the plants will survive but will gradually lose vigour.

Propagation

As well as dividing plants, you can take basal cuttings in spring when you lift the plants and store them in trays of moist compost; they'll soon produce young shoots. Cut them off close to the base of the plant and root them in moist perlite, or a mix of sand and compost, kept in a warm place.

Take cuttings from the parent plant in mid-winter and place them in moist perlite. Cuttings should produce roots by March and be ready for planting outdoors in May. Pinch back (see below) spray varieties as soon as the cuttings have rooted to promote bushy growth. Then feed and water well. Outdoor varieties should be happy with less attention, provided they're grown in reasonably fertile soil.

Disbudding

The group called 'disbudding chrysanthemums' (e.g. 'Regalia' and 'Dorridge Beauty') perform better if the side buds are nipped off to leave a single, larger flower. Without disbudding, they often produce congested stems of flowers that are inclined to be top heavy.

Pinching back

Also known as stopping, you should pinch back the larger-flowered kinds by removing the top bud of the single stem. This results in new side shoots; select the two strongest and remove the rest. Once they've lengthened, pinch out their tips to encourage two more stems to form. Consequently, a single cutting will produce four blooms. If you want more flowers, which will be smaller, leave three new shoots instead of two after each pinching.

Staking

Most chrysanthemums, particularly the taller kinds, need support. Use metal linking stakes (available from garden centres) or canes and pea sticks with string. If you plan to grow your chrysanthemums in large drifts, try fixing a horizontal layer of wide-mesh bean netting above the plants at a height of around 45cm (18in). It may initially look unattractive but provides good support once the plants have grown through the netting, which makes it worth the wait.

Avoid over-feeding, especially the spray varieties, because the taller, lanky plants become very floppy and the lush growth also invites disease.

Control fungal diseases, such as powdery mildew, with specific fungicides. Plants forming warty patches on their undersides are suffering from white rust and should be destroyed.

Eelworm produces browning leaves but can be cured by heat-treating the plants. Dig up the plants, wash off the soil and immerse the roots in water at a temperature of 46°C (115°F) for five minutes.

Indoor and greenhouse varieties are more prone to pests and diseases; regularly check each plant carefully.

Remove any aphids promptly as they can introduce viruses.

National collections of chrysanthemums:

Outdoor hardy Chrysanthemums
J Barker
64 Morris Way
London Colney, ,
Hertfordshire
AL2 1JN
Tel: 01727 822564
Opening times: By appointment only

Indoor Chrysanthemums
M Darwell - NC Coordinator, Leeds City Council
Stable Courtyard
Temple Newsam Estate
Leeds
Yorkshire, LS15 9TP
Tel: 01437 710 542
Opening times: Open daily during daylight hours

Leucanthemum collection
A D Allen
The Shapcott Barton Estate
East Knowstone
South Molton
Devon, EX36 4EE
Tel: 01398 341664
Opening times: By appointment only