Chrysanthemums offer valuable, late flowers in September and October. These perennial plants are either hardy or half-hardy and can be grown in containers, as house plants or in a border – the trick is to buy the right chrysanthemum for the job. You can also grow annual chrysanthemums, which are used in summer bedding displays, such as Chrysanthemum ‘Sunset’.
Chrysanthemums flower in an incredible range of different colours. Flower shapes can vary, too, from reflexed, single or pompom and more. Spray chrysanthemums form a number of flowerheads on one stem and are often grown under glass for cut flower production. Early-flowering chrysanthemums can be planted in ornamental borders and will flower from late summer to autumn. Late-flowering chrysanthemums flower in winter and are grown as house plants. For a reliable perennial chrysanthemum, choose hardy garden varieties that can be left in the ground all year round. Otherwise, dig up and store in autumn, as you would dahlias.
How to grow chrysanthemums
Chrysanthemums are sold as rooted cuttings or small plants, in spring. Pot these on at home and plant out after all risk of frost has passed, from late May. Grow in moist but well-drained soil with added compost or well-rotted manure in a sunny, sheltered spot. Pinch out spray chrysanthemums and ‘disbud’ (remove the sideshoots from) single-bloom chrysanthemums. All chrysanthemums need staking. Lift in autumn, cut back and store in a dry, frost-free place.
Tender chrysanthemums can be grown as house plants or in the greenhouse for cut flowers. Alternatively grow them in pots and bring them undercover in autumn to continue flowering. Cut back and store after they’ve finished flowering as you would with outdoor varieties.
Think chrysanthemums have fallen out of favour? Find out why Monty Don thinks we should all be growing more of them, in this clip from Gardeners’ World:
Where to plant chrysanthemums
Early-flowering chrysanthemums or hardy garden chrysanthemums require a sunny, sheltered position in the garden border. They are perfect for the middle of a mixed border.
Tender chrysanthemums should be grown in he greenhouse or in pots which can be placed outside in summer and brought in s the weather turns in autumn.
How to plant chrysanthemums
Pot on rooted cuttings and small plants bought from garden centres into individual 10cm pots and 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 fertilizer. Provide support straight away.
Rooted cuttings of tender (indoor) chrysanthemums can be planted direct into greenhouse beds or large pots, under cover.
Monty Don shows you how to give your borders a boost with richly coloured chrysanthemums, which should flower well into autumn. Using bronze-yellow Chrysanthemum ‘Pennine Jude’, he shows you how and where to plant them and explains what conditions these traditional half-hardy perennials need:
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 flower buds start to open.
When spray chrysanthemums reach about 20cm in height, pinch out the growing point to encourage side shoots to form. This will result in more flowers. Disbud single-bloom chrysanthemums to concentrate the plant’s energy into its flower. Simply remove the side-shoots (as you would with tomatoes) so the plant grows one strong single stem.
In sheltered gardens half-hardy, early-flowering chrysanthemums can be cut back to the ground in autumn and left to overwinter in the garden. Otherwise lift them. You can either replant them into your greenhouse to continue flowering or cut them back to store over winter.
Late-flowering chrysanthemums should be potted into a loam-based compost and grown in a sunny spot outdoors in summer. In late summer move plants to a cool room in the house of about 10°C and wait for flowers to open. Don’t allow plants to dry out.
How to propagate chrysanthemums
Propagate chrysanthemums from basal stem cuttings in spring. The time to take them is when you see healthy new shoots appearing at the base of the plant. Take cuttings when the shoots are about 6cm above ground. Water the parent plant well the day before. Remove cuttings with a sharp knife and then peel off the lower leaves. Leave at least three leaves at the top of the cutting. Trim the base of the cutting to give a clean, straight finish. Insert the cutting into a pre-watered pot of cutting 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 them to grow on in a frost-free place.
Growing chrysanthemums: problem-solving
The chances of chrysanthemums being affected by pests and diseases is reduced if plants are given the right growing conditions.
One of the most common ailments is white rust. This is fungal disease that is spotted in late summer or autumn. The surface of leaves are covered in sunken light brown spots and the undersides with off-white pustules. Chrysanthemums can also be affected by the less problematic brown rust.
As with all fungal diseases, the problem is worse in a wet autumn. Plants will become weak and stunted and they can look dreadful. If you spot the problem, quickly remove and burn any infected leaves. The fungus can make it through the winter on rootstocks of plants. Treat with a suitable fungicide and avoid taking cuttings from diseased plants.
Chrysanthemums for cut flowers
Chrysanthemum flowers will last for three weeks in a vase. Refresh the water regularly and keep in a cool room to extend the show.
Chrysanthemum varieties to try
- Chrysanthemum ‘Leading Lady’ – giant, incurved, soft pink blooms in late summer. Half-hardy, early-flowering type. Reaches 120cm
- Chrysanthemum ‘Early Yellow’ – fully hardy perennial with small single flowers from July to October. Reaches a height of 80cm
- Chrysanthemum ‘Spartan Fire’ – reflexed red flowers with the underside of the petals coloured gold. Fully hardy perennial. Height 1m
- Chrysanthemum ‘Foggy’ – a late-flowering type for indoor display, Lime-green pompon flowers from November. Height 80cm. Protected by Plant Breeders Rights
- Chrysanthemum ‘Bruno Bronze’ – a tender perennial with bronze flowers from September to November. Perfect for cutting. Height 1m