Dahlias in Little Lyde

Dahlia pinnata

Dahlia
Dahlia · 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.

100 cm · Full Shade · High Water

Calibrated to Little Lyde · last frost ≈ 4 May

Sow indoors March to April, plant out April to June. Frost risk October to May.
ActivityJanuaryFebruaryMarchAprilMayJuneJulyAugustSeptemberOctoberNovemberDecember
Sow indoorsNoNoYesYesNoNoNoNoNoNoNoNo
Plant outNoNoNoYesYesYesNoNoNoNoNoNo

Growing guide

Step-by-step instructions for growing Dahlia

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. 01

    Start Tubers Indoors

    23 Mar to 6 Apr

    Place tubers in trays with moist compost, eye-side up, and cover lightly. Keep at in a bright spot indoors from 23rd March - 6th April. Water sparingly until shoots appear.

    • Only moisten the compost if it feels dust-dry, overwatering at this stage quickly causes tuber rot. If the tuber arrived soft, dry it for a day before potting.
  2. 02

    Pot On Shoots

    20 Apr to 27 Apr

    Once shoots are tall, pot each tuber into individual containers with multi-purpose compost from 20th April - 27th April. Grow on in a bright, frost-free place.

    • Support the tuber from underneath when potting on, not by the shoot. Dahlia shoots are brittle and snap with very little pressure.
  3. 03

    Harden Off Plants

    11 May to 18 May

    Gradually acclimatise plants to outdoor conditions over 10-14 days from 11th May - 18th May. Place outside during the day and bring in at night, avoiding frost.

  4. 04

    Plant Outdoors

    18 May to 1 Jun

    Transplant into well-drained, fertile soil in full sun after frosts from 18th May - 1st June. Space plants apart and water in well. Use fleece if cold nights are forecast.

    • Set the tuber so its neck sits 10–15 cm below soil level. This anchors the plant against wind and protects the crown.
  5. 05

    Support and Pinch

    1 Jun to 8 Jun

    Insert stakes at planting to support tall stems. Pinch out the growing tip when plants reach to encourage bushiness from 1st June - 8th June.

    • Tie main stems to the stake every 30 cm using soft garden twine in a figure-of-eight loop. This stops stems rubbing and snaps in strong winds.
  6. 06

    Feed and Water

    8 Jun to 30 Sept every 2 weeks

    Water regularly to keep soil moist, especially in dry spells. Feed every 14 days with a high-potash fertiliser from 8th June to boost flowering. Stop feeding by 30th September.

    • Once soil is warm, apply a 5 cm layer of organic mulch like leaf mould or compost, leaving a gap around the stems to prevent collar rot.
  7. 07

    Deadhead Regularly

    20 Jul to 7 Oct

    Remove spent flowers weekly from 20th July to encourage continuous blooms. Cut back to a leaf joint to promote new buds.

    • Spent dahlia flowers have a pointed, cone-shaped seed head behind the petals. New buds are round and firm be careful you don't remove them.
  8. 08

    Lift and Store Tubers

    21 Oct to 4 Nov

    After the first frost blackens foliage, cut stems back and carefully lift tubers from 21st October - 4th November. Dry, label, and store in frost-free conditions in dry compost or sand over winter.

    • Lift with a garden fork, not a spade, to avoid spearing tubers. After lifting, dry them upside down for a few days so moisture drains from the hollow stems.

Companion plants

Tap a plant to see why it works (or doesn't) with Dahlia.

Good companions

Plants to avoid

Why companion planting matters

Companion planting can deter pests, improve pollination, and make better use of space. Some plants confuse pests or attract beneficial insects; others improve soil or offer shade to neighbours that need it.

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.

Dahlia guides by town

See how Dahlia timing shifts in other towns with different frost dates.