Should you deadhead dahlias? Gardening experts weigh in

With the summer season truly upon us, it's time to get out into the garden and enjoy to the blooming flowers we spent all winter tending to. But what to do with those flowers with wilted heads? 

No matter what garden trend you're following this year, some flowers will never go out of style and one of those is dahlias. Some of the best plants to have in your garden, dahlias can provide a range of colours and textures to your space. 

But what happens when their flowers are spent, looking withered and rather drab? Should you deadhead dahlias? 

We asked gardening experts if they recommend deadheading them and whether leaving them is more beneficial to the plant. Here's what they said... 

Should you deadhead dahlias? 

Whilst you may already know how to deadhead peonies and have mastered pruning your rose bush, is the rule the same for dahlias? The bushy perennial brings a true array of colours to your garden with its pointed petals and textured pattern. So it's important to know how best to maintain them. 

"Deadheading dahlias is a good way to keep them blooming throughout the season. Remove spent flowers and the plant will focus on making more blooms rather than setting seeds. This keeps your garden looking tidy and guarantees you get the most flowers out of your dahlias," explains Jane Dobbs, lead gardener at Allan's Gardeners. 

So when it comes to how to sort the garden out, add deadheading your dahlias to the list, alongside deadheading irises and roses.

Jane Dobbs

Gardening is Jane's passion, having built and maintained stunning outdoor spaces for over a decade. Managing all the garden projects at Allan's Gardeners is her responsibility as lead gardener. A wide range of horticultural practices come into play in Jane's work, from landscape design to plant and lawn care. 

What are the benefits of deadheading dahlias?

There are various benefits to deadheading your dahlias, most are similar to why you should deadhead your clematis too. 

Aside from the benefit previously mentioned by Jane, she also points out that deadheading is a great way to stop your plant from self-seeding too much. She says, "This might be useful depending on your garden. Dahlias need deadheading for better flowering and overall health. Additionally, by deadheading, you help reduce the chance of fungal diseases and pests."

Speaking to professional gardener and author Sarah Raven, she is also quick to highlight how deadheading can help promote growth for your dahlias next year. She explains, "Whilst deadheading does help prevent diseases, it also allows the plant to focus its energy on root development and next year’s flowers." 

So if you're into succession planting deadheading is a great way of getting more out of your dahlias each year. 

Sarah Raven

Since the publication of her first book, The Cutting Garden, Sarah has led the way in introducing a new kind of productive gardening. Her aim is to create intense colour and beauty, combined with a practical and easy-to-achieve approach. Her popular gardening podcast Grow, Cook, Eat, Arrange has achieved 4.1 million downloads. She’s published 15 books and runs Sarahraven.com.

How to deadhead dahlias

Now you know all the great reasons for deadheading your dahlias, how can you do it? Knowing how to deadhead plants properly is an extremely important task and a gardening tip that every gardener should know. 

"Flowers that are faded, wilted, or no longer vibrant should be removed. To follow the stem of a flower, trace it down to where it meets the main stem or branch and cut the flower stem just above the nearest set of leaves or leaf joints with sharp, clean scissors or pruning shears," says Jane. 

She continues, "It's usually at this point that you see new growth. Gather spent blooms and dispose of them to keep the garden tidy and prevent the spread of disease." 

This is a great opportunity for composting, making your own compost is not only a great sustainable garden idea but it'll also give you an endless supply when you're next repotting your plants. 

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Once you deadheaded your plants Jane says don't stop there. She explains that you should continue deadheading your dahlias as the new blooms fade throughout the season. 

"Your garden will look neat and you'll get more flowers. Dahlias can get tall, especially the ones with bigger flowers, so stake them. Keep them from breaking or bending by using bamboo stakes," Jane finishes, such as these Bamboo Stake Garden Plant Flower Support Sticks at Amazon.