Pinching out (stopping)
Once young plants reach about 20cm (8in) tall, in early summer, pinch out the main growing point to encourage branching. You can also pinch out the tips of sideshoots as they grow, until about mid-summer. This will help to create stockier plants that will carry more flowers.
Watering
Newly planted chrysanthemums, in borders or containers, need regular watering through the growing season. Never let the soil or compost dry out completely. But take care not to overwater too, as they dislike waterlogged conditions.
Feeding
To boost growth, apply a general fertiliser, such as Growmore or blood, fish and bone, towards the end of April.
You can also apply a nitrogen-rich feed in June, to further encourage lush growth. Use sulphate of ammonia or, for organic gardeners, dried poultry manure pellets, following the instructions on the pack.
During flowering, to maximise the display, you can give a weekly high-potassium feed, such as tomato fertiliser.
Mulching
Apply a thick layer of mulch to the soil surface after planting. This will help to hold moisture in the soil and prevent weed germination. Use well-rotted manure or garden compost.
If leaving plants in the ground over winter, insulate the roots with a thick layer of mulch in late autumn.
Removing some flower buds (disbudding)
Disbudding is a specialist technique used to produce very large blooms or well-balanced clusters to use as cut flowers or for exhibition:
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On 'spray' chrysanthemums – these produce clusters (sprays) of flowers. If you remove the large central flower bud, you'll get a more uniform display of evenly sized blooms.
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On single-flowered chrysanthemums – keep the main central flower bud and remove all the side buds and other shoots. The plant will then put all its energy into producing one spectacular flower.
Deadheading
Removing faded flowers regularly helps to keep the display looking its best. It also encourages new buds to form, extending the overall display.
See our guide to deadheading.
Overwintering
Most hardy chrysanthemums can survive temperatures down to at least -5˚C (23˚F). However, in much of the UK temperatures can fall below this, so it may be safer to lift and store plants over winter in light, frost-free conditions, such as a frost free greenhouse, a cool conservatory, porch or similar. Plants in exposed or poorly drained sites will particularly benefit.
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Once flowering has finished, cut down the stems to about 20cm (8in) tall, to produce what is known as a stool
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Lift the shortened plants and shake off the soil from the roots
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Snip off any green shoots and leaves, so you have bare stems
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Label each plant, if you have several different types
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Stand the stools in a shallow tray, on a 5cm (2in) layer of slightly damp compost. Cover the roots lightly with loose compost.
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Store in a cold but frost-free location, such as a cool greenhouse or conservatory, or a garage
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Keep the compost just moist through the winter
In mild regions
Where temperatures are unlikely to fall below -5˚C (23˚F), especially in sheltered gardens with well-drained soil, you could risk leaving plants in the ground through winter.
Even so, it's best to give them some protection:
In containers
Plants in containers are particularly vulnerable to cold, so bring them indoors once flowering has finished. Keep them frost free, such as in a cool greenhouse or enclosed porch.
In very mild regions, you could risk leaving them outside, in which case:
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Move them to a warm, sheltered spot, such as in the lee of a wall or under the eaves
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Wrap containers in insulating layers of fleece, to protect the roots.
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Make sure the compost doesn't get waterlogged – stand containers on bricks (or pot feet) to keep the drainage holes clear
