Claus Dalby on how to create a wonderful display with dahlias in pots

August 7th, 2021 Posted In: Garden trends & design, Gardening know how

Gardener, photographer and author Claus Dalby has a display of dahlias in  pots that look like a glorious herbaceous border.

There must be several hundred pots massed together, with both dahlias and other plants. The display can be switched around when a flower goes ‘over’ or if the colour balance needs a boost.

Claus Dalby

Claus Dalby and his ‘border’ of colourful dahlias in pots. They combine beautifully with foliage plants and lilies, also all in pots.

Claus is famous on Instagram and he has a beautiful Claus Dalby YouTube channel, where he shares tips and inspiration from his garden. He is Danish, although the YouTube channel is in English. It’s about ‘gardening, hygge and Scandinavian lifestyle.’ He’s written 30 books on design and lifestyle in Danish, and his first book in English will be out next year.

The garden is near Aarhus in Denmark, which has a roughly similar climate to the UK and to USDA Zone 8. But, of course, one of the wonderful things about pots is that you can switch plants around or bring them inside easily if you need to. A pot-based garden is ideal if you want to grow plants that may be a little too tender for your climate.

A large garden sub-divided into smaller gardens

Claus’s garden is around an acre, but is divided up into 15 ‘rooms’. Each zone is a small garden in itself. So his ideas work for small, large and middle-sized gardens.

When he first moved in, it was mainly laid to lawn. Now there isn’t an inch of lawn left. There are lots of inspiring elements, such as hornbeam trees pruned ‘umbrella style’. But, above all, it’s Claus’s use of colour and pots that is so exceptional.

So I’ve asked Claus to show us how he creates his container gardens. The full interview and fabulous views of his garden are in this video on YouTube, but I’ve summarised the main points here.

Do dahlias grow well in pots?

They certainly do. Claus grows most of his dahlias in pots and the display is fabulous. He grows a wide range of varieties, sizes and colours.

Dahlia grower Sarah Raven suggests that you should choose the shorter dahlias for pots because they’re less likely to flop. But Claus puts a circular support onto the pot at the time of planting so he is able to grow the bigger dahlias in pots, too.

In fact, most plants will grow in pots, including trees. (See here for general tips on growing plants successfully in pots.)

How to plant dahlias in pots

Claus begins in April, which is early spring in Denmark. He first puts the dahlia tubers into standard plastic pots. The pots are not much bigger than the dahlia tubers, so they fit quite snugly. He then adds just a thin layer of soil on top. ‘I put just 1cm of soil on top of the plants,’ he says. ‘They seem to start to grow quicker.’

He keeps these pots of dahlias in a frost-free greenhouse.

After around 5 weeks, the early foliage of the dahlias has emerged. So he plants them into their permanent containers. Once again, he plants quite snugly. ‘I sometimes put three tubers into a large pot,’ he says. In smaller pots, he’ll just put one tuber.

At this stage, he’ll also fix the support for bigger dahlias into their pots.

Dahlias in pots need regular fertilisers and watering.

What to plant with dahlias in containers

Claus says that plant partnerships are very important. Most of his pots only have one variety of plant in them. But the whole display mixes a wide variety of plants in pots. It is a beautifully balanced riot of colour.

He plants annuals in pots, such as cleomes, as well as shrubs like ninebark and philadelphus. Any plant will grow in a pot, at least for a few years.

Repeat the varieties of plant in the grouping

Claus believes that repetition is very important when planning either a border or a grouping of pots. You will see the same lilies, begonias and dahlias repeated along the pot grouping.

Grouping of pots by Claus Dalby

The chartreuse green foliage of Aralia cordata ‘Sun King’,Phsyocarpus ‘Nugget’ and Philadelphus ‘Aureus’, and the bright orange of the begonia add zing to this grouping of pots. And you can see the lilies, dahlias and other plants are repeated at intervals.

His next tip for creating a dramatic colour grouping – plant some pots with contrasting lime green or ‘chartreuse’ foliage. It sets off the dark leaves and rich colours of the dahlia flowers. His favourites include Aralia cordata ‘Sun King’, Physocarpus ‘Nugget’ and Philadelphus ‘Aureus’.

Dahlias and other plants in pots

The splashes of citrus green and orange really make this display of pots work. The orange begonia is Begonia bertinii.

The philadelphus and physocarpus can grow quite tall, but Claus cuts them down to 20-25cms in spring. New, bright green foliage springs back. You don’t get the flowers if you cut them back in spring. But Claus likes these plants for their foliage not their flowers.

Another way of adding that splash of citrus bright is to include a flower like orange begonias to the group.

Add height to the grouping of pots

The next tip is to add contrast with height. ‘Spikes are very important’ in the pot display, explains Claus. Plant some taller, upright plants in your grouping with the dahlias.

Many of the plants in Claus’s pots are ones we normally think of as border plants.  For example, he has Cleome Violet Queen, Buddleias Purple, Angelica Gigas and Verbena bonariensis.

Cleome 'Violet Queen'

I haven’t seen Cleome ‘Violet Queen’ grown in pots before, but it looks wonderful in Claus’s garden.

He also has lilies, which grow particularly well in pots. Many people keep their lilies in pots and wedge them into the border in time for a beautiful display, then whisk them out when they are over.

Lily Purple Marble

Lily ‘Purple Marble’ , grown in pots in Claus’s ‘pot border’.

Contrast flower sizes

If you have large flower heads, such as dahlias, in a border or grouping of pots, Claus adds contrasting small flower heads. For example, verbena bonariensis, which is tall and airy, with tiny flower heads. In spring, he cuts the verbena bonariensis plants back to about 10cm, which makes them more bushy and less tall when they flower in summer.

What to do with dahlias in pots over winter

Claus takes all the dahlia tubers out of his pots for the winter. He cleans the soil off and wraps them in newspaper. ‘Then store them somewhere where the temperature doesn’t go below around 5C,’ he says. ‘It’s important that they don’t freeze.’

He re-uses the same tubers the following year, planting them out in plastic pots in early spring.

There’s more advice on looking after dahlias in winter here.

More about dahlias and pots

To find out more about growing dahlias, see our ‘what you need to know about growing dahlias’ post. And for more ideas and inspiration on grouping pots, see 5 ways to use garden planters, plus potscaping tips. And, of course, because plants like dahlias are dormant in winter, here’s some inspiration on what to put in your pots in winter!

Dahlias in pots and borders need regular dead-heading, so I keep a pair of snippers by the back door. I can just pop out when I have a moment and snip off any dead or dying flower heads. The more often you do this, the more flowers you get. So don’t leave dead-heading to a once-a-week-job in the garden.

I use Darlac snips, which were recommended by Frances Moskovits. I wrote about her borders in ‘How to Make a Garden Border Look Amazing’, which has been one of the Middlesized Garden’s most popular posts. The Darlac snips are available on the Middlesized Garden Amazon shop (please note that Amazon links are affiliate, see disclosure.)

But if you don’t want to do dead-heading, then find out how evergreen plants work brilliantly in pots to give you year-round interest.

Pin to remember dahlias in pots

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5 comments on "Claus Dalby on how to create a wonderful display with dahlias in pots"

  1. Teresa Pedley says:

    I have alot of Dahlias after moving house in June and they haven’t bloomed in their containers as usual. I want to put new plants in our new bigger garden but the soil is quite clayish. Can I leave my tubers out over winter if I cover them with a layer of bark mulch? Also, what can I do to I inject colour on a small budget into my very green garden to see me through to winter?

    1. I wouldn’t advise planting the dahlias until the frosts have planted in the spring. I tried it once, on the grounds that dahlias survive in my soil over winter, so maybe I could plant them in autumn….but it didn’t work. A very budget conscious friend of mine gets her garden through winter by buying pansies from the supermarket and putting them in her pots (as the dahlias are best taken out of them and wrapped up in newspaper). She makes it look special by picking just one or perhaps two colours of winter pansies rather than the usual multi-coloured selection. Keep dead heading and they should go on to Easter. I hope that helps.

  2. Isobel Reid says:

    Hello thank you for a very inspirational post.
    I don’t have a greenhouse, so would the dahlias be ok in a cold frame?
    Thank you

    1. Depending on your winters, a cold frame may be a bit too cold. They don’t need light when they’re dormant, so a garage, shed or unheated cellar would be fine. Unfortunately, they shouldn’t be too warm either or they will think it is spring, so taking them in to a centrally heated house probably wouldn’t be a good idea. If you do put them in the cold frame, you could wrap them both in newspaper and then a layer of horticultural fleece and hope not to be covered in snow for months on end!

      1. Isobel Reid says:

        Thank you x

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