Growing Dahlias
I love growing Dahlias, they are a stunning addition to any garden, offering a vibrant display from midsummer until the first frost.
Their variety in colour, shape, and size makes them a favourite amongst gardeners and allotmenteer's. I started growing Dahlias about 5 years ago with just a few tubers and have added to them gradually.
Whether you’re a beginner or an experienced grower, this guide will help you cultivate beautiful dahlias in your garden
Choosing the Right Dahlias
Dahlias come in a wide range of forms, from small pompon varieties to large dinner-plate blooms. When selecting dahlias, consider your garden’s space and the effect you want to create.
If like me you want to grow for cutting flower, consider this when making your selection as some variety's are better than others for cutting as they grow a longer stems. Popular types of Dahlia include:
Decorative Dahlias – Large, showy blooms perfect for borders.
Cactus Dahlias – Spiky, dramatic petals.
Pompon Dahlias – Small, rounded flowers ideal for cut arrangements.
Bishop Dahlias – Dark foliage with single flowers, great for pollinators.
When and How to Plant Dahlias
Dahlia tubers should be planted in late spring, once the risk of frost has passed (typically from mid to late May in most parts of the UK). Here’s how:
Choose a sunny spot – Dahlias thrive in full sun with well-drained soil.
Prepare the soil – Enrich with compost or well-rotted manure for added nutrients.
Planting depth – Place the tubers around 10-15cm deep with the growing eye facing upwards and last years stem at the surface.
Spacing – Leave about 45-60cm between plants to allow for proper growth.
Watering – Keep the soil moist but avoid waterlogging.
Getting ahead- You can start your Dahlias early in pots. Provided they are kept frost free in a greenhouse. Planting in pots early will give you good strong plants ready to plant out after the last frost.
Dahlia Tuber Offshore Dream.
Caring for Dahlias
Feeding – Apply a high-potassium fertiliser (such as tomato feed) every couple of weeks during the growing season.
Supporting – Taller varieties may require staking to prevent damage from wind.
Deadheading – Regularly remove spent blooms to encourage continuous flowering.
Pest Control – Keep an eye out for slugs, snails, and aphids, particularly on young shoots.
Overwintering Dahlias
Dahlias are not fully hardy in the UK, so they need protection over winter. You have two main options:
Lifting Tubers – After the first frost, cut down the foliage, carefully lift the tubers, dry them out, and store them in a cool, dry place.
I lifted my dahlias at the end of the last season because the tubers where big enough to split and make more plants. after drying them off I stored them over the winter in one of the greenhouses protected from the cold and frost.
Mulching in Place – In milder regions like Dorset you can leave tubers in the ground, covering them with a thick layer of mulch to insulate against frost. This is the method I have used in the past and the tubers have been fine overwinter. I put a layer of straw over the bed and then a layer of manure, if I have leaves I will also add these and then finally I cover the area with black plastic.
Enjoying Your Dahlias
With the right care, dahlias will reward you with months of spectacular blooms, that you can enjoy year after year. They also make fantastic cut flowers, brightening up your home with their vivid colours.
Over the past few years I have added to my Dahlia collection creating a colour pallet of pinks, whites and purples in different shapes and textures. The bee's love them too!
Are you growing dahlias this season? Share your tips and favourite varieties as we love to hear what your growing.
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