Dahlias have had quite a rocky history when it comes to gardening trends. They so often fall all too easily into the ‘love em or hate em’ category; lumped into a single generalisation of taste that accounts for little by way of individual colour, shape, spread and most importantly, application. From their first boom in popularity around the 40s and 50s, all the way through to their much more recent return in the catalogues of Sarah Raven and J.Parkers, these multi-coloured and most striking of plants have endured an ever-fluctuating criticism unrivalled in the gardening world. Nevertheless, a passion for them remains, and the diversity of the retailed dahlia is now vast.
For me, dahlias have become a most dependable and rewarding ally, both as a cut flower and as that crucial lift in the mid Summer border. In fact here at the garden they are a crucial part of the design; printed boldly into the initial planting layout sheets themselves, long before I arrived. Their role is considered essential to the central garden concept in fact, acting to lighten the atmosphere and make fun of the stern and imposing brickwork of the house. Each year as the tulips die back, are removed from the cutting beds and dried out, the over-wintered dahlias are dug back in their rows, ready to continue the show on into Autumn. These offer a continuous supply of cut flowers for the house, while at the same time making large, conspicuous spectacles of colour and form.
However, as the late colour-planting wizard Christopher Lloyd recounts, their attraction ought not simply reside in seeing them lined-out in a designated, separate bed or border. They should instead be ‘assimilated into the garden’s fabric’, this being, as he notes, ‘by far the most appealing way to see them’. And I would agree. In the long border this year I decided to repeat a few particular dahlias; using them as structured colour first and foremost. Once established and kept as slug-free as possible, I’ve found that they form reliable, continuously flowering mounds, drawing together the otherwise scattered individuals within the planting. This effect is further pronounced when there are one or two other plants also repeated throughout the border. The picture below shows bronze ‘Babylon’ dahlias mixing with the blue of the geraniums, coupled along the bed. They’re just getting started now, but will soon make quite an impression.
Back in the cutting rows however, I’ve been lining out dahlias for picking. It’s a simple task, and a nice one on a decent, warm day. There are a few key points to remember when planting out dahlias however, and if put in place from the very start, they can save you a lot of time.
Dahlias have two main enemies; slugs and the wind. Being a plant that grows both very tall and very fleshy, it’s exposed to the perils of a heavy wind and to the inexhaustible appetite of night-creeping molluscs. If a dahlia is simply planted out and left to its own devices, chances of survival, let alone fruition, are pretty slim. Especially in a British climate.
A third danger comes in the form of soil compaction. Dahlias prefer a rich, free-draining soil and, much like their potato relatives, suffer badly from damp, saturated conditions, leading to rot. So the first thing to do is make sure that, once their position is decided, a large and deep hole is dug. If the soil isn’t free draining enough as it is, grit needs to be added to the bottom in order to improve drainage.
The roots then need to be teased out a little, as with ordinary practice when planting out, before firmly placing it into the hole and lightly filling in around. Lightly is the key, as this is another opportunity for compaction to take place.
Next comes staking. Staking is a necessary evil unfortunately, but depending on your method and material, the results needn’t be an eyesore. Like many gardeners, I usually prefer to use canes of hazel or birch to support herbaceous plants, as they’re generally much more aesthetically sympathetic to the planting. However when it comes to dahlias, a good, sturdy bamboo will do the job, and placed deep and indiscreetly within the foliage, you’d never know it was there. In this case it’s definitely function over beauty that matters. The swaying, flower-bearing shoots are then tied in, making sure to secure the knot on the cane, rather than the plant.
Lastly a thick mulch of gravel is layered around the base. This will act as a barrier for slugs and snails, making it difficult to access the plant. I usually combine this with removing some of the lowest leaves, so as to make the journey even more of a likely dead-end for them. From then on, the method of slug removal is down to the individual, and where you stand on slug pellets, inorganic or organic. I prefer to avoid them altogether, although this does result in a lot of hand removal, which isn’t much fun, but you get used to it!
Provided the plants remain regularly watered and tied in, that’s about it. And the reward will far outweigh the initial planting effort.
I couldn’t agree more with your sentiments about dahlias. I have several of Christopher Lloyd’s books and love seeing how he integrates them into the mixed borders. I’ve not thought of getting just one color and repeating throughout the entire bed. I think I’ll give it a try next season.