dahlia tubers, dahlia planting

Dahlia Tubers: Tips for Planting Dahlia in the UK

Dahlias are a popular choice for gardeners in the UK, and it’s easy to see why. With their vibrant colours and unique shapes, their beauty can add a touch of beauty to any garden. However, planting and caring for dahlia can be pretty tricky. That’s why we’ve put together this comprehensive guide to help you grow beautiful dahlia in your garden. This blog covers everything from selecting the suitable dahlia tubers to nurturing them through the growing season. We’ll also provide tips on dealing with common pests, deadheading for prolonged blooming, overwintering techniques, propagating your collection and troubleshooting problems that may arise. 

Know more about dahlia

Understanding Dahlia: An Overview

Dahlias are vibrant flowers that bloom in late spring and autumn, offering a wide range of colours. These tender perennials require proper care for healthy growth. Gardeners love dahlias for their vibrant petals and various shapes and sizes. Planting dahlia in a sunny spot with well-drained soil is ideal, while regular deadheading and mulching help prevent pests and diseases. With their stunning blooms, dahlias add colour to any garden decoration, lighting up sunny borders through summer and into late autumn.

The Perennial Nature of Dahlia

Dahlias are known for their perennial nature, being able to survive and regrow for multiple years. Originally from Central America and Mexico, these plants store nutrients in their tubers, similar to bulbs, supporting their growth during dormant periods. Proper protection from frost and pests is crucial to ensure the survival of dahlia tubers. In regions with harsh climates, dahlias may need to be divided or lifted and stored during winter. With the proper care, these beautiful flowers from Mexico can provide stunning blooms year after year.

Selecting the Right Dahlia Tubers

Choosing tubers of different sizes allows for various flower types and heights in your garden. You can select from other dahlias, such as cactus dahlias with spiky petals or anemone dahlias with a central pom-pom surrounded by petals. Look for healthy tubers without any signs of rot or damage. It’s advisable to purchase tubers from reputable nurseries or online sources to ensure quality. Lastly, select tubers that match your desired colour scheme and garden style. Consider including single dahlias such as ‘Joe Swift’ and ‘Bishop of Llandaff’, which have a single ring of petals that circle a central disc. This type of dahlia is attractive to pollinators.

What Colour Dahlia to Choose for Your Garden

When selecting dahlia for your garden, you’ll have many colours, including vibrant shades of red, orange, pink, yellow, purple, and rhs. These vibrant flowers allow you to create a visually stunning display. Consider your garden’s overall colour scheme and theme when deciding on dahlia colours. You can choose complementary or contrasting colours to add visual interest and diversity to your flower bed. Also, remember that dahlia petals’ colours can attract pollinators to your garden.

When is the Best Time to Plant Dahlia Tubers in the UK?

Late spring or early summer is the best time to plant dahlia tubers in the UK once the risk of frost has passed. The soil should be warmed up to around 10°C (50°F). Starting tubers indoors in February/March can give them a head start, and young plants can be planted outdoors once frost danger has ultimately passed. For early flowering, start tubers in pots of compost during March and April and keep them in a greenhouse or windowsill. Harden off, ready for planting outdoors in late May / early June when the danger of frost has passed.

Preparing for Planting in Autumn: Key Tips

To prepare for planting dahlia in autumn, start by clearing the planting area of debris and weeds. Enhance the soil quality by incorporating organic matter like compost or well-rotted manure. Ensure proper drainage to prevent waterlogging and potential root rot. Consider planting dahlia in raised beds or containers if you have heavy clay soil. Additionally, protect newly planted dahlia from frost by covering them with mulch.

How to Plant Dahlia Tubers?

To plant dahlia tubers, dig a hole wide and deep enough for the tuber. Please place it in the spot with the growing point facing up and cover it with soil, leaving the top leaves above the surface. Firmly press the soil and water thoroughly for root growth.

Dahlia Planting Process Step-by-Step

  • Select a sunny spot in your garden.
  • Make the soil soft using a garden fork or tiller, dig holes 15-20 cm deep, and spaced about 60 cm apart.
  • Position the tubers in the gaps with the growing point facing upwards.
  • Backfill the holes with soil and water the area thoroughly.

This ensures that the young plants have the right conditions to grow. Compact varieties don’t need so much space, so that you can plant them closer together, around 30-50cm apart. With this step-by-step process, you can successfully plant dahlias for vibrant blooms.

Grow single flowered dahlia

Nurturing Your Dahlias: Comprehensive Care Guide

Regular watering during dry periods ensures the soil remains consistently moist, providing the conditions for dahlia growth. Feed dahlia with a balanced fertilizer once every month during the pulping season to promote healthy growth and abundant blooms. Tall varieties should be staked to prevent them from toppling over in strong winds. Deadheading faded flowers encourages continuous blooming and prevents seed formation. Protect dahlias from common pests like aphids, earwigs, snails, and slugs using organic pest control methods.

How to maintain a flowering farmhouse

Regular Watering and Feeding for Healthy Growth

To ensure healthy growth, regular watering and feeding are crucial for dahlias. Watering them consistently is essential, ensuring the soil doesn’t dry out completely between waterings. Use a watering can or drip tray irrigation system to deliver water directly to the plant’s roots, avoiding excessive wetting of the foliage. A natural homemade liquid fertilizer every few weeks during the growing season will supply the necessary nutrients. Mulching around the base helps retain moisture and suppress weed growth. Monitor soil moisture levels closely and adjust watering frequency per weather conditions.

Organic fertilizers that boost garden growth

Importance of Staking Dahlias

Staking is crucial for tall dahlia plants, supporting and preventing them from bending or breaking. Properly staking dahlias can prominently display their blooms, adding colour and beauty to your garden. Staked plants are also less susceptible to wind damage, ensuring their longevity. Additionally, staking promotes even growth, preventing sprawling and creating a more compact appearance. Substantial stakes offer vital support during heavy rainfall, protecting the plants and preserving their health.

Dealing with Common Dahlia Pests

Consider using neem oil to keep aphids under control on your dahlias. Slugs and snails can be kept away by placing copper tape or eggshells around the base of the plant. Spider mites, tiny pests, can be controlled by spraying them with a strong blast of water or by using a miticide. You can set earwig traps using rolled-up newspapers or empty oil-filled tuna cans. Japanese beetles can be handpicked or controlled with a natural insecticide like spinosad.

How to Protect Dahlias from Earwigs and Slugs?

Use diatomaceous earth, a natural insecticide, to protect your dahlias from earwigs and slugs. Another method is placing copper tape around the base of the plant to deter slugs. Handpicking pests off your dahlias can be effective but time-consuming. Lastly, keep your garden clean to eliminate hiding places for these pests.

Maintaining Aesthetic Appeal: Deadheading Dahlias

Regularly deadheading dahlias is essential for maintaining their aesthetic appeal. By removing spent blooms, you encourage the plant to produce more flowers, extending the flowering period. This practice also helps promote healthy growth and prevents the plant from diverting energy into making seeds. Use sharp, clean shears or scissors to avoid damaging the plant. Deadhead at least once a week to keep your dahlias looking their best. Consider leaving some flowers on the plant to produce seeds for future plantings. To encourage more flowering side shoots, pin the main growing tip down to the top pair of leaves. This technique, mentioned in the blog “Dahlias in the UK: Planting Tips”, helps the plant grow more vigorously and produce more beautiful blooms.

How to Deadhead Dahlias for Prolonged Blooming?

Cut deadhead dahlia stem just above the first set of leaves and below the spent bloom to promote prolonged blooming. Regularly remove spent flowers throughout the blooming season for continuous flowering. Properly dispose of the spent blooms to prevent disease and pests.

Ensuring Longevity: Overwintering Dahlias

To ensure the longevity of your dahlias, it’s essential to take proper steps for overwintering. Start by cutting back the plant, lifting the tubers, and storing them in a suitable location. Keep the tubers dry and check for any signs of rot or damage. For success, replant the tubers in the UK at the right time, following timing guidelines. Disease prevention and pest control strategies are also crucial, such as avoiding overcrowding and using natural remedies.

Steps to Overwinter Dahlia Tubers

There are a few key steps to ensure the successful overwintering of your dahlia tubers. First, wait until the first frost before digging up your tubers. Once dug up, cut off the foliage and allow the tubers to dry for a few days. Next, remove any remaining soil and check the tubers thoroughly for any signs of damage or disease. Always store the tubers in a cool and dry place, such as a garage or basement, and check on them periodically during winter to ensure they are not rotting or drying out.

Propagating Dahlias: How to Increase Your Dahlia Collection?

Increase your dahlia collection through division, stem cuttings, or seed. Divide tubers into smaller pieces with at least one eye each. Take stem cuttings from the top of the plant and root them in soil or water. Collect and plant mature seeds to grow dahlias from seed.

Cutting Dahlias for Propagation: A Detailed Guide

  • Start by choosing a healthy seed.
  • Use a sharp plant knife or scissors to remove lower leaves and flowers and remove basal cuttings.
  • Join the fresh cut ends in rooting hormone before planting in a moist medium.
  • Keep the cuttings warm and humid until roots form.
  • Transplant the rooted cuttings to pots or the garden.

Troubleshooting Common Dahlia Problems

 Identify common pests and diseases, such as aphids and powdery mildew, and take preventive measures like regular inspection and proper sanitation. Ensure well-draining soil and consistent moisture levels to prevent issues like root rot. Adequate sunlight and temperature conditions and protecting the plants from frost promote optimal growth. Staking and pruning help avert stem breakage and encourage healthy development.

Why are My Dahlias Not Blooming in the UK?

  • Poor soil drainage.
  • Insufficient sunlight.
  • Planting too early before the danger of frost has passed.
  • Pest infestation.
  • Failure to deadhead spent blooms.


Dahlias are beautiful and vibrant flowers that can bring life to any garden. Following the above mentioned planting tips can ensure a successful and thriving dahlia garden in the UK. Every step is crucial for their growth and longevity, from selecting suitable tubers to providing proper care and maintenance. Remember to water and feed them regularly, stake them for support, protect them from pests, deadhead for prolonged blooming, and overwinter the tubers for future seasons. If you found these tips helpful, don’t forget to share them on social media and inspire others to grow dahlias in their gardens, too.

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