Garden chrysanthemums flower from late summer to autumn, when little else is in bloom. Flowers come in a range of different colours, sizes and shapes, and can be single or double-flowered – ‘spray’ chrysanthemums form a number of flowers on one stem. Chrysanthemums make excellent cut flowers that can last for up to three weeks in a vase, and they work well in dried arrangements, too.
Garden chrysanthemums can be annual or perennial, and hardy or half-hardy. For a reliably perennial chrysanthemum, choose a hardy varieties, which will survive winter outside so you can leave it in the ground and it will come back the following year. Half hardy varieties won’t survive UK winters and should be dug up in autumn to overwinter in a greenhouse – they may continue flowering until December.
Bear in mind that garden chrysanthemums are not the same plants as indoor chrysanthemums, which are sold as house plants. Indoor chrysanthemums are tender and must not be taken outside in autumn and winter. They are best treated as cut flowers as you’re unlikely to encourage them to flower again after they have finished blooming.
When to plant chrysanthemums
Chrysanthemums are sold as rooted cuttings or small plants, in spring. Pot these on at home and then plant out after all risk of frost has passed, from late May. Alternatively, buy garden-ready chrysanthemums in summer and autumn for immediate planting.
Where to plant chrysanthemums
Chrysanthemums can be grown in pots or garden borders. Choose a sunny, sheltered position with fertile, well-drained soil.
In this clip from Gardeners’ World, Monty Don explains where to plant chrysanthemums:
View Green Video on the source website
How to plant chrysanthemums
Pot on rooted cuttings and small plants bought from garden centres into individual 10cm pots and then pot on again when their roots have filled their growing space. Plant out after all risk of frost has passed, into moist but well-drained soil in a sheltered, sunny spot. Dig plenty of organic matter into the planting hole or apply a general purpose fertiliser. Provide support straight away.
Monty Don demonstrates how to pot up rooted chrysanthemum cuttings, in this clip from Gardeners’ World:
View Green Video on the source website
How to care for chrysanthemums
Water regularly in summer and feed container-grown plants with a liquid fertiliser from late spring. Stop feeding as soon as the flower buds start to open.
If growing spray chrysanthemums, pinch out the growing tip when stems reach about 20cm, to encourage side shoots to form. This will result in more flowers. Deadhead single-bloom chrysanthemums to concentrate the plant’s energy into producing new flowers. Simply remove the side-shoots (as you would with tomatoes) so the plant grows one strong single stem.
In sheltered gardens where soil drains freely, leave hardy chrysanthemums in the ground to overwinter in the garden. Otherwise dig up and either replant them into your greenhouse to continue flowering or cut them back to store over winter in pots or trays of compost, kept barely moist.
How to propagate chrysanthemums
The easiest way to propagate chrysanthemums is to take basal cuttings in spring. Some species can be propagated by seed – simply remove the seeds when they’re brown and dry and store them in an envelope in a cool, dry spot until you can sow them in spring.
How to take chrysanthemum cuttings
Chrysanthemums are straightforward to propagate from basal stem cuttings in spring. Take cuttings when the basal shoots are about 6cm above ground. Water the parent plant well the day before, and then take the cuttings with a sharp knife, peeling off the lower leaves so at least three leaves remain at the top of the cutting. Trim the base of the cutting to give a clean, straight finish, and then insert it into a pot of moist cuttings compost.
Place the pot in a propagator or cover with a clear plastic bag. Keep in a light, warm place. When you see good signs of growth, remove the bag and leave the cutting to grow on in a frost-free place. When the cuttings are growing strongly, pot individually into 10 cm pots and grow on until well established.
Pests and diseases
Chrysanthemums are liable to several different pests, including aphids, red spider mite, leaf miner, and eelworms. Inspect plants regularly and tackle pests as soon as the first signs appear, by hand-squashing or by removing infected leaves.
One of the most common ailments is white rust, a fungal disease that may appear in late summer or autumn. The surfaces of leaves are covered in sunken light brown spots and the undersides with off-white pustules. Quickly remove and burn or bin any infected leaves.
Chrysanthemum varieties to grow
Chrysanthemum ‘Bruno Bronze’ – a tender orange chrysanthemum, flowering from September to November. Perfect for cutting. H x S: 1.2m x 30cm
Chrysanthemum ‘Polar Star’ – a fast growing, showy annual that flowers in summer. H x S: 75cm x 40cm
Chrysanthemum ‘Green Mist’ – has striking green flowers, making a statement both in the border and the vase. H x S: 50cm x 50cm
Chrysanthemum ‘Ruby Mound’ – bears large double ruby red flowers from late summer into autumn. H x S: 50cm x 50cm
Chrysanthemum ‘Misty Cream’ – has large, pom-pom-like, fully double flowers in yellow-cream, and can bloom into November. More suited to the cuttings patch rather than as part of an ornamental border. H x S: 50cm x 50cm
Frequently asked questions
Do chrysanthemums survive over winter?
Hardy varieties of chrysanthemums can survive winter outside if their planting site is sheltered and sunny, with soil that drains freely and doesn’t become waterlogged. In colder areas, or if growing half-hardy types of chrysanthemum, cut back and lift plants in autumn and move under cover to a greenhouse.
Do chrysanthemums grow back each year?
Hardy and half-hardy chrysanthemums grow back the following year if overwintered properly. Make sure hardy varieties overwinter in soil that doesn’t become waterlogged, and half-hardy varieties are overwintered under cover, such as in a greenhouse.
