Delightful dahlias

Outdoor Living

The beautiful Cornel Brons

In the Garden

Eriko Hopkinsons

August is here, and I am still travelling around my homeland - the sub-tropical islands of Okinawa. While I’m looking at bougenbryas and hibiscuses, I am thinking about my dahlias in the cool air of Ireland.
I really think that Ireland is an ideal place to garden (even though we lack sunshine from time to time), especially with the encroachment of climate change illustrated by the recent wildfires in Europe.
In Okinawa, under the scorching subtropical sun, gardening is minimal, consisting merely of watering and tidying the undergrowth in the early morning.
Dahlias, cannas, and all other sun-loving plants weren’t initially on my list of must-haves for my garden, perhaps because I grew up in a warm climate and didn’t think they would survive in Ireland.
My previous garden wasn’t south facing, and therefore wasn’t particularly sunny (though it was sheltered with layers of trees and shrubs all around). I tried growing some dahlias in the flower beds here and there, but they never achieved their full potential.
The creation of a cutting garden in the middle of an open patch, dedicated to dahlias and vegetables, finally did the trick. Dahlias need rich and well drained soil, sun, and their own space. Provide these, and they will achieve their full potential.
We used to dig up their overwintering tubers in autumn and plant them in pots in spring, and then plant them back into the ground again after the danger of frost had mostly passed (not easy when frost sometimes hits in the middle of June!).
But over time, my dahlia collection got out of hand, and this method became too much work. So, we decided to experiment by leaving some tubers in the ground, covered with bracken and then plastic sheeting.
After the first frost hits the dahlias, we cut them back to the ground and mulched them with cut bracken (you can use straw or other convenient substitutes) and then covered them with recycled (ours came from the neighbouring farmer) black plastic. As dahlia tubers hate cold, soggy ground, make sure you do this before the winter rain starts.
Then, in spring (sometime in April or May), take a peep under the cover - if the tubers are shooting up, take the plastic sheet off and make sure slugs don’t damage the new growth. If frost is forecast, cover the shoots with bracken again. I used organic slug pellets while the dahlia tubers were small (from Fruithill Farm in Cork) which are not harmful to other wildlife, but once the tubers become large and vigorous, they can combat slugs by themselves.
In May, sprinkle compost, seaweed or well rotted manure (whichever you prefer), then make a plant support system. We used bent construction metal bars, then put gridded pea nets across the bars, 80cm to a meter high above the ground. If your dahlia patch is small, you can use bamboo canes or shop-bought plant supporters.
You’ll be glad you’ve done this when they start to grow tall and then high winds are forecast!
Another important trick is to dead head throughout the season to keep them flowering.
Dahlias are invaluable plants that reward you with endless flowers until the first frosts in autumn. The astoundingly vibrant colours and shapes of dahlias are irresistible (there are over 57,000 registered cultivars!) and flamboyant, easily making me forget about their only fault - no scent.
My old favourites are the incredibly large but serene ‘Cafe au Lait’, the deep magenta ‘Thomas Edison’, the dark red ‘Nuit d’Ete’, the exquisite cerise to peach gradation of ‘Labyrinth’, and the sweetest little orange spray of ‘New Baby’.
There are also some modest single flowered species (for example, ‘Dahlia Imperialis’/tree dahlias) and varieties like the ‘Bishop’s Children’ series. These single flowered dahlias can easily be grown from seeds, and they are beloved by bees. I admired the tall pale pinky-yellow single flowered dahlias in June Blake’s garden last year.
There are some good suppliers of dahlia tubers at present; Peter Nyssen and Farmer Gracy are both based in the UK, but they supply to Ireland without extra taxes, and you can choose from their entire amazing collection.
I hope readers have enjoyed the Clew Bay Garden Trail this year. It’s such a joy to open our gardens and share our enthusiasm and labours of love with the public. Thank you all for visiting and donating to our chosen charities. These rewards will keep us going through another year of gardening!

Eriko Hopkinson is a member of the Clew Bay Garden Trail. A chain of beautiful and unique private gardens, the trail opens to the public during summer to raise funds for charity (see for more). Each month, an article by a trail member will appear in these pages.