Dahlia

Dahlias in Abbey St Bathans

Dahlia pinnata

Show-stopping tuberous perennials that provide a spectacular display of colour from mid-summer right up until the first frosts. Ranging from enormous 'dinner plate' blooms to intricate pompoms and open-centred varieties that bees adore, they are a staple of the late summer UK garden.

Height100cm
SunlightFull Shade
WaterHigh Water

Growing Guide

Step-by-step instructions for growing Dahlia

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Growing Guide for

Change the guide to see different planting timelines and tips.

The most common UK method, starting tubers indoors in spring and planting out after frosts for summer blooms.

1
Start Tubers Indoors

3 Mar - 17 Mar

Place tubers in trays with moist compost, eye-side up, and cover lightly. Keep at in a bright spot indoors from 3rd March - 17th March. Water sparingly until shoots appear.

2
Pot On Shoots

31 Mar - 7 Apr

Once shoots are tall, pot each tuber into individual containers with multi-purpose compost from 31st March - 7th April. Grow on in a bright, frost-free place.

3
Harden Off Plants

21 Apr - 28 Apr

Gradually acclimatise plants to outdoor conditions over 10-14 days from 21st April - 28th April. Place outside during the day and bring in at night, avoiding frost.

4
Plant Outdoors

28 Apr - 12 May

Transplant into well-drained, fertile soil in full sun after frosts from 28th April - 12th May. Space plants apart and water in well. Use fleece if cold nights are forecast.

5
Support and Pinch

12 May - 19 May

Insert stakes at planting to support tall stems. Pinch out the growing tip when plants reach to encourage bushiness from 12th May - 19th May.

6
Feed and Water

20 Sept - 19 May
every 2 weeks

Water regularly to keep soil moist, especially in dry spells. Feed every 14 days with a high-potash fertiliser from 20th September to boost flowering. Stop feeding by 19th May.

7
Deadhead Regularly

27 Sept - 30 Jun

Remove spent flowers weekly from 27th September to encourage continuous blooms. Cut back to a leaf joint to promote new buds.

8
Lift and Store Tubers

11 Oct - 25 Oct

After the first frost blackens foliage, cut stems back and carefully lift tubers from 11th October - 25th October. Dry, label, and store in frost-free conditions in dry compost or sand over winter.

Companion Plants

Plants that grow well (or poorly) with Dahlia

Why Companion Planting Matters

Companion planting can help deter pests, improve pollination, enhance growth, and maximize garden space. Some plants release chemicals that repel pests or attract beneficial insects, while others can improve soil quality or provide shade for sensitive plants.

Suggested Varieties

Popular varieties of Dahlia to consider

Bishop of Llandaff

A classic variety with dark foliage and bright red flowers, ideal for borders and excellent for pollinators.

Café au Lait

Popular for weddings, with large, creamy-pink blooms that can reach up to 25cm across.

Happy Days

A compact bedding type, perfect for containers, with prolific flowering in mixed colours.