Chrysanthemums, often referred to simply as 'mums', are a popular and vibrant group of flowering plants in the Asteraceae (Daisy) family. Cultivated for over 2,500 years, they hold deep cultural significance in many parts of the world, symbolising longevity, rejuvenation, and nobility in various traditions.
Chrysanthemums come in a dazzling array of colours — white, yellow, red, pink, purple, and bronze — and display a wide variety of flower forms, including daisy-like singles, pompons, buttons, cushion, and spider shapes. Their striking blooms typically appear in late summer to autumn, making them a favourite for seasonal gardens and cut flower arrangements.
Beyond their ornamental appeal, some chrysanthemum varieties are used in herbal teas and traditional medicine, known for their calming and anti-inflammatory properties. In the garden, they are appreciated for their relative hardiness, bushy habit, and ability to attract pollinators such as bees and butterflies during the late season when many other flowers have finished.
Available as hardy perennials or tender annuals depending on the variety, chrysanthemums are versatile plants suited to beds, borders, and containers. With their beauty, diversity, and cultural richness, they remain a beloved choice for gardeners and florists worldwide.
How To Grow
Growing Chrysanthemums
Choosing the Right Type
Garden chrysanthemums (hardy mums) are best suited to outdoor growing and can survive winter in the ground with protection. Florist mums are more tender and better suited to container growing or indoor display.
Starting Plants
Chrysanthemums can be grown from seed, cuttings, or divisions. Sow seed indoors 8–10 weeks before the last expected frost, pressing seeds lightly onto the surface of moist compost — they need light to germinate. Cuttings taken from established plants in spring root readily and produce more reliable plants than seed-grown specimens.
Site and Soil
- Sunlight: Full sun is essential — aim for at least 6 hours of direct light daily
- Soil: Well-draining, fertile soil with a slightly acidic to neutral pH (6.5–7.0)
- Avoid low-lying areas or heavy clay where water pools, as root rot is a common problem
Planting Out
Transplant young plants outdoors after all risk of frost has passed in spring, spacing them 45–60 cm apart to allow good airflow and bushy development.
Watering
Water consistently at the base of the plant to keep soil evenly moist. Avoid overhead watering to reduce the risk of fungal diseases. Reduce watering slightly once plants are established.
Feeding
Apply a balanced, slow-release fertiliser in spring to support leafy growth. Once flower buds begin to form, switch to a fertiliser higher in phosphorus and potassium to encourage strong, abundant blooms.
Pinching Back
Pinch out the growing tips (about 2–3 cm) every 2–3 weeks from planting until midsummer. This promotes a bushy, compact habit and significantly increases the number of flower stems. Stop pinching in midsummer to allow buds to develop for the autumn display.
Mulching
Apply a layer of organic mulch around the base of plants to retain moisture, suppress weeds, and protect the root zone from temperature fluctuations.
Overwintering
After flowering has finished and the first frosts arrive, cut plants back to approximately 15 cm above the ground. In colder areas, apply a generous layer of straw or dry leaves over the crown to protect roots through winter. In milder areas, light mulching is generally sufficient. Lift and store tender varieties in frost-free conditions.
Harvesting
Harvesting Chrysanthemum Blooms
Best Time to Harvest
For cut flowers, harvest in the early morning or late afternoon when temperatures are cooler and stems are well-hydrated. Cut blooms when the outer petals are just beginning to unfurl but the centre of the flower is still relatively tight. Flowers harvested at this stage will continue to open in the vase and will last significantly longer than those cut in full bloom.
Tools
- Sharp, clean scissors, garden shears, or floral snips
- A clean bucket or vase filled with cool water, ready to receive stems immediately
How to Cut
- Select healthy stems with unblemished foliage and well-formed buds
- Make a clean cut at a 45-degree angle, approximately 10–15 cm below the flower head (or longer for arrangements)
- Remove all leaves that would fall below the waterline in a vase to prevent bacterial rot
- Place stems immediately into cool water
Post-Harvest Care
- Keep cut chrysanthemums away from direct sunlight, heat sources, and ripening fruit (ethylene gas accelerates ageing)
- Change the water every two days and re-cut the stems at an angle to prolong vase life
- With proper care, cut chrysanthemums can last 2–4 weeks in a vase
Drying Flowers
To preserve blooms, hang whole stems upside down in a dark, dry, well-ventilated space for 2–3 weeks until fully desiccated. Dried chrysanthemums retain good colour and can be used in wreaths and dried arrangements.
Encouraging More Blooms
Regular harvesting and deadheading of spent flowers prevents the plant from setting seed and encourages it to produce further flushes of bloom throughout the flowering season.
Common Problems
Common Problems with Chrysanthemums
Pests
Aphids Clusters of small soft-bodied insects on young shoot tips and undersides of leaves. They weaken growth and can transmit viruses. Control with a strong jet of water, insecticidal soap spray, or by encouraging natural predators such as ladybirds and lacewings.
Spider Mites Tiny mites that cause fine speckling and bronzing of leaves, often with visible webbing. Most common in hot, dry conditions. Improve air circulation, increase humidity around plants, and treat with neem oil or appropriate miticide if infestations are severe.
Earwigs Earwigs feed on petals overnight, leaving ragged holes. Trap them in rolled damp newspaper or small pots filled with straw placed near plants, then dispose of traps regularly.
Leafminers Serpentine pale trails appear within the leaf surface where larvae are feeding. Remove and destroy affected leaves promptly to reduce spread.
Diseases
Powdery Mildew A white or grey powdery coating appears on leaves and stems, particularly in warm, dry conditions with poor air circulation. Ensure good spacing between plants, avoid overhead watering, and treat with a sulphur-based fungicide or diluted bicarbonate of soda spray if needed.
Botrytis (Grey Mould) Fuzzy grey mould develops on flowers and foliage in cool, wet, humid conditions. Remove affected material immediately, improve ventilation, and avoid wetting foliage when watering.
Root Rot Caused by waterlogged soil, resulting in wilting, yellowing, and eventual plant collapse even when watered. Ensure excellent drainage and do not overwater. Raised beds or adding grit to heavy soils can help.
Verticillium Wilt A soil-borne fungal disease causing yellowing, wilting, and browning of lower leaves. There is no cure — remove and destroy affected plants and avoid replanting chrysanthemums in the same soil for several years.
General Tips
- Rotate planting positions each year to reduce soil-borne disease build-up
- Deadhead spent blooms promptly to improve airflow and deter botrytis
- Avoid excessive nitrogen fertilisation, which encourages soft, pest-susceptible foliage at the expense of flowers
