Bishop of Llandaff
A classic variety with dark foliage and bright red flowers, ideal for borders and excellent for pollinators.
When to plant Dahlias in Cardiff
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 Sun · High Water
Calibrated to Cardiff · last frost ≈ 22 Apr
| Activity | January | February | March | April | May | June | July | August | September | October | November | December |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Sow indoors | No | Yes | Yes | No | No | No | No | No | No | No | No | No |
| Plant out | No | No | No | No | Yes | No | No | No | No | No | No | No |
Growing guide
What to do through the growing season
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.
01
Sow Seeds Indoors
25 Feb to 11 MarSow thinly on moist seed compost from 25th February - 11th March. Cover lightly and keep at in the light. They take 7–14 days to come up.
02
Prick Out Seedlings
11 Mar to 1 Apr Dates as each sowing reaches this stageOnce they have true leaves, pot them on from 11th March - 1st April. Hold the leaves, not the stem, and keep them in good light.
03
Harden Off Plants
22 Apr to 6 MayHarden off from 22nd April - 6th May over 10–14 days. Give them a little more outdoor time each day, and keep them off frost and strong wind.
04
Plant Outdoors
6 May to 20 MayPlant out after frost from 6th May - 20th May, in beds or pots. Space cm apart in full sun and water in. Use a cloche if a cold night is coming.
05
Pinch for Bushiness
20 May to 10 Jun Dates as each sowing reaches this stageFrom 20th May - 10th June, pinch the growing tip when plants are so they make more shoots and flowers.
06
Water and Feed
27 May to 14 Oct Dates as each sowing reaches this stage Optional · repeat every 2 weeksKeep the soil moist. Feed with a balanced liquid fertiliser every 14 days from 27th May until 14th October.
07
Deadhead Flowers
15 Jul to 21 Oct Dates as each sowing reaches this stageTake faded blooms off from 15th July, snipping just above a leaf node so new buds follow.
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
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.
Related plants
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Calabrese
Sow indoors March, plant out May, harvest July to September. Frost risk October to April.
Dahlia guides by town
See how Dahlia timing shifts in other towns with different frost dates.