Dahlias in Achrimsdale
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.
Growing Guide
Step-by-step instructions for growing Dahlia
Planting Calendar
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
Place tubers in trays with moist compost, eye-side up, and cover lightly. Keep at in a bright spot indoors from 28th March - 11th April. Water sparingly until shoots appear.
2 Pot On Shoots
Once shoots are tall, pot each tuber into individual containers with multi-purpose compost from 25th April - 2nd May. Grow on in a bright, frost-free place.
3 Harden Off Plants
Gradually acclimatise plants to outdoor conditions over 10-14 days from 16th May - 23rd May. Place outside during the day and bring in at night, avoiding frost.
4 Plant Outdoors
Transplant into well-drained, fertile soil in full sun after frosts from 23rd May - 6th June. Space plants apart and water in well. Use fleece if cold nights are forecast.
5 Support and Pinch
Insert stakes at planting to support tall stems. Pinch out the growing tip when plants reach to encourage bushiness from 6th June - 13th June.
6 Feed and Water
Water regularly to keep soil moist, especially in dry spells. Feed every 14 days with a high-potash fertiliser from 13th June to boost flowering. Stop feeding by 8th September.
7 Deadhead Regularly
Remove spent flowers weekly from 25th July to encourage continuous blooms. Cut back to a leaf joint to promote new buds.
8 Lift and Store Tubers
After the first frost blackens foliage, cut stems back and carefully lift tubers from 29th September - 13th 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
Plants to Avoid
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.
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