Dahlia

Dahlias in Edinburgh

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.

Growing dahlias from seed for bedding varieties, sown indoors in early spring for summer flowers.

1
Sow Seeds Indoors

18 Feb - 4 Mar

Sow seeds thinly on the surface of moist seed compost in trays from 18th February - 4th March. Cover lightly and keep at in a bright spot. Germination takes 7-14 days.

2
Prick Out Seedlings

11 Mar - 18 Mar

Once seedlings have true leaves, transplant into individual pots from 11th March - 18th March. Handle by leaves to avoid stem damage and grow on in good light.

3
Harden Off Plants

22 Apr - 29 Apr

Acclimatise plants to outdoors over 10-14 days from 22nd April - 29th April. Increase exposure gradually, protecting from frost and strong winds.

4
Plant Outdoors

29 Apr - 13 May

Transplant into beds or containers after frosts from 29th April - 13th May. Space apart in full sun and water well. Use cloches if needed for early planting.

5
Pinch for Bushiness

20 May - 27 May

Pinch out the growing tip when plants are tall from 20th May - 27th May to encourage side shoots and more flowers.

6
Water and Feed

27 May - 22 Sept
every 2 weeks

Keep soil consistently moist. Feed with a balanced liquid fertiliser every 14 days from 27th May to support growth and flowering until 22nd September.

7
Deadhead Flowers

15 Jul - 29 Sept

Remove faded blooms regularly from 15th July to prolong flowering. Snip off just above a leaf node to encourage new buds.

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.