Make your garden last longer with dahlias

September 11th, 2016
Posted In: Garden trends & design, Gardening know how

Dahlias are one of the most valuable plants if you want a long flowering season. But they have been unfashionable until recently.

A typical dahlia border used to look like a fruit salad. There were random mixes of brightly coloured dahlias in white, yellow, red and pink. And they stood in serried rows without any under-planting.

Context is everything in gardens. So now many gardeners use dahlias differently. You can see new, interesting directions in foliage. And we partner dahlias with a wide range of other flowers to create dramatic effects.

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Design ideas and tips - dahlias for contemporary gardens

‘Few plants can rival dahlias if you want a long season in your garden,’ says Steven Edney, head gardener at The Salutation garden in Sandwich, now closed. ‘They flower from two to five months at a time, depending on your climate.’

Steven has dahlias in his blood. His family bred dahlias. He has been part of the RHS dahlia trials at Wisley, and he has now created a beautiful dahlia garden at The Salutation.

How to use dahlias to give a long season of colour

Dahlia ‘Weddington Farm’ was bred by Steven’s father. It has survived for 30 years over winter and summer at Steven’s family home. Here it borders the Salutation’s vegetable garden.

The Salutation was designed by Lutyens. Steven joined eleven years ago to restore the Grade 2 Listed garden. At that point, there was a mound of rubbish and rubble instead of a vegetable patch. It is now a delightful mix of dahlias and vegetables.

Dahlia design ideas

The Salutation, appropriately, has Lutyens benches. Surrounded here by the pink ‘Gracie M’ dahlia and red ‘Mountain Fire.’

Colour theme your dahlia border

Dahlias used to be planted alone in beds, in a riot of contrasting colours. There is a traditional dahlia bed at The Salutation, where the colours move through the colour wheel. Reds and pinks are followed by purple, yellow and white. Stripes and multi-coloured dahlias are at the end.

How to use vibrant red and orange dahlias

Reds and oranges at one end of the dahlia trial bed.

There is a trial bed, where Steven subjects his dahlia types to the kind of treatment they would get in an ordinary middle-sized garden.

‘I don’t water them, and I only feed them with a manure mulch and some blood, fish and bone,’ he says. ‘That’s what most domestic gardeners would do, and it’s important to see how they survive in non-professional gardens before we sell them to the public.’

Even so, the dahlia bed is colour-themed, with dark reds, pinks, peaches, yellows and moving harmoniously through the colour spectrum.

Tips for incorporating long lasting dahlias into your garden

There are conventional beds planted only with dahlias at the Salutation. These are arranged by colour – reds and pinks going into peaches and yellows, and so on.

Think about the foliage as well as the flowers

I love the use of foliage and colour in The Salutation’s dahlias.

Design tips for dahlias

A peach dahlia is married with a bronze background foliage. Bring the dahlia colour alive by thinking about the foliage colour of the plant next to it.

New ideas with dahlias

This foliage combination also marries veg and dahlia – this is an Australis hybrid dahlia with kale in one of the ornamental borders.

New dahlias

Steven is always growing and trialling new dahlia seedlings and crosses. He sees how the public responds to the new varieties. Dahlias are tested for a couple of years to make sure they come back true and are reasonably hardy.

New dahlia trends - darker leaves and single flowers

Three different orange dahlia seedlings developed at The Salutation in an orange grouping with marigolds, nasturtiums and ricinus.

Dahlia ideas and tips

There are three kinds of orange dahlia being trialled here. The bees like them all.

Use dahlias in exotic gardens

Dahlias were originally imported from Mexico, so they can be considered ‘exotics’. With bright colours and sharp sculptural shapes, dahlia flowers are an ideal choice for exotic gardens. The Salutation has an Exotic garden just by the entrance. Steven and his team are planning to expand it next year.

How to use dahlias for exotic effects

Dahlia ‘Mel’s Orange Marmalade’ with banana palms and tree ferns in the Salutation’s Exotic garden

‘I’m very influenced by Gertrude Jekyll,’ says Steven. ‘She combined exotic plants like ricinus with dahlias in her own garden.’

Steven’s own garden, created with his partner, Lou Rawle, is an exotic garden, also featured on this blog.

Exotic new dahlia trends

Another vivid orange dahlia (‘Babylon Gevland’) gives jungle colour to the exotic garden.

Combine dahlias with vegetables

As well as extending the flowering season in the garden, dahlias last a long time in the vase. They are cut-and-come-again flowers, which means that the more you cut them, the more flowers you’ll get.

How to grow dahlias for the house and the garden

Dahlias in the vegetable garden at The Salutation.

Dahlias were, in fact, originally imported as food. The tubers are like potatoes, apparently. Personally, I can’t quite bring myself to try them. If, however, you dig your dahlias up at the end of the season, you could roast them.

How to use dahlias in your vegetable garden

Dahlia with chard leaves in the vegetable garden.

At the Salutation, the dahlias in the veg beds are partnered with kale, chard, pernilla for leaf contrast.

How to use dahlias in veggie gardens

Dahlias with espaliered fruit trees. This is Dahlia ‘Happy Single Party’. I wonder how it came by the name?

Ideas for dahlias with veggies

Perilla is a very popular salad leaf in Japan. Here it’s partnered with a dahlia seedling.

New dahlia trends in pots

Dahlia ideas for pots and containers

Combine a dahlia with a grass. Here Dahlia ‘Double Tally Ho’ is planted with Panicum ‘Frosted Sensation.’

Dahlias with sculpture

Dahlia ideas for your garden or back yard

The Salutation has many sculptures by Emily Stone. Here a bronze iris is flanked by red Dahlia ‘Tally Ho and yellow Dahlia ‘Mystic Illusion.’

A simple recipe for an eight-month border

This is a simple border plan which can be in flower from February to October, depending your climate. There are bulbs in the border at the beginning of the year, with bergenias in the front. Then irises and peonies take over, followed by dahlias. The orange dahlia is City of Alkaar.

Dahlias - plants for long season borders

This border repeats one kind of dahlia (‘City of Alkaar’). in between, there are peonies and irises.

Easy ways to deal with dahlia problems

I’ve found dahlias very easy to grow, but they do have a few problems. They get eaten by slugs. The flowers can be nibbled by earwigs. And there’s also the thought of digging them up and storing them over winter. But all three of these problems are relatively easy to deal with.

How to use dahlias in your garden

A dahlia nibbled by earwigs. You can see the jagged edges of the petals.

Steven recommends using Growing Success, an organic-approved slug remedy and also a wool-based mulch which slugs don’t like crawling over. Use these from February onwards. Once the plants are big enough in June and July, slugs and snails won’t matter so much.

Steven gardens in a wildlife-friendly way. For example, to deter earwigs, he puts a mixture of molasses and boric acid in a flowerpot and puts it upside down on a stick. The earwigs crawl in and die, but they’re not poisonous to any other wildlife that eats them.

Dahlias are easy to grow

Dahlia ‘Merckii’ is a species dahlia, which means it’s very close to the wild form. The closer a plant is to its wild form, the hardier and more resilient it tends to be.

As for digging your dahlia tubers up in winter, Steven suggests you don’t dig them up. He has dahlias that have over-wintered in the ground for thirty years. He covers them with mulch to protect them from frost. Not all will survive, but a surprising number will. ‘Christopher Lloyd threw all his dahlias out at the end of every season,’ he says.

If your dahlias don’t survive the winter, buy new ones.

Sculpture at the Salutation

No dahlias – but a striking sculpture by Paul Cummins at the Salutation.Do join us for middle-sized garden tips and inspiration every Sunday morning. Enter your email address in the box in the heading and we will pop into your inbox at dawn on Saturday mornings!

See the Salutation and Steven’s top dahlia growing tips in video

6 comments on "Make your garden last longer with dahlias"

  1. Love the 8 month border idea!

    1. So do I, although I think I am not personally disciplined enough as a gardener – I’d always be popping other things in.

  2. Great article, very pleased you enjoyed your visit, but felt I had to correct that the Salutation Dahlia Festival is on September 17th and 18th!

  3. Only have a small garden love dahlias flower all summer and last into autumn just leave them in ground and they flower every year

    1. They are wonderful – dahlias were the first flowers that made me think I could garden.

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