Dahlia Week: Tips from the Top

Last Saturday we were lucky enough to hear from two of the dahlia world’s greatest enthusiasts as part of a Dahlia Festival at The Salutation in Sandwich. As well as being the garden’s full time Head Gardener, local lad Steven Edney is also an RHS trial judge and dahlia committee member. He gleefully describes dahlias as ‘generous, joyful flowers’. Steven was accompanied by Andy Vernon, dahlia fanatic and author of The Plant Lover’s Guide to Dahlias which I reviewed last August.

During an hour-long guided walk of The Salutation’s dahlia collection we were treated to explanations of how the team trial and select dahlias for the garden, what makes a garden-worthy hybrid and how to protect plants from pests and diseases without resorting to chemicals.

An unknown, but rather splendid dahlia
An unknown, but rather splendid dahlia

Steven began by explaining that this part of east Kent offers ideal growing conditions for dahlias. The soil is deep, rich and silty. The earth warms up quickly in spring meaning that tubers grow away fast once the final frosts have passed. Horse manure is added to the trial beds in spring, but after that plants are left to their own devices so that they display their inherent vigour and disease resistance. “A good dahlia should hold its flowers aloft, well above the foliage”, explained Steven. Trial beds are situated in different parts of the garden; some in full shade, some on open ground and others in places where the plants are only in sun for part of the day. It was fascinating to see which cultivars flowered best and where. I was especially interested to discover several blooming prolifically in the most shaded plot.

The man himself, Steven Edney, Head Gardener at The Salutation
The man himself, Steven Edney, Head Gardener at The Salutation

Sunlight hours in east Kent are the longest in the country and perfect for horticulture and agriculture, which is why the county is often known as The Garden of England. This suits dahlias which are genetically programmed to start producing flowers once the days begin to shorten after mid-summer.

Dahlia 'City of Alkmaar'
Dahlia ‘City of Alkmaar’, a cactus type favoured at The Salutation

At The Salutation chemicals are used only in the most extreme circumstances. Steven prefers to trade a certain amount of damage by the dahlia’s greatest foes – slugs, snails, red spider mites, capsid bugs and earwigs – in return for a less polluted, more sustainable environment. Strong, well-grown plants will usually shake off all but the most determined pest attacks. Andy Vernon chipped in to offer a great tip for reducing earwig damage in dahlias: paint the inside of a terracotta plant pot with boric acid mixed with molasses or honey. Pack the pot with straw and then invert over the top of a bamboo cane. The earwigs will creep inside, ingest the sweet nectar laced with boric acid (harmless in the environment) and then feed it to other earwigs. The boric acid will build up in the earwig population and eventually kill it off.

To prevent slug and snail damage, The Salutation’s gardening team use natural sheeps’ wool pellets. The slimy pests can’t slither over the irritating fibres, which in turn decompose slowly to enrich the soil and feed the plants.

The dark-leaved dahlia trial demonstrates some startling contrasts
The dark-leaved dahlia trial demonstrates some startling contrasts

Steven is keen to start naming some of his own hybrid seedlings, one of which he showed us (below) growing in a border beneath the terrace of the magnificent Lutyens house. It has rich, bronzy leaves and white flowers heavily flushed with magenta. It looked like a winner to me. He introduced us to another cultivar which he has called ‘Weddington Pink’, a catus type bred by his grandfather that possesses incredible vigour and, again, white blooms flushed pale pink.

A new dahlia seedling. Could this be the next 'Bishop of Llandaff'?
Steven’s new dahlia seedling. Could this be the next ‘Bishop of Llandaff’?

Let’s be clear, Steven Edney is evangelical about dahlias. After an hour in his presence, backed-up by Andy Vernon, it was easy absorb his immense enthusiasm. “Gardens are like an autobiography” says Steven, “you only buy plants you like”. That would be why there were dahlias as far as the eye could see.

Dark leaved dahlias need sunshine to bring out their vibrant shades
Dark-leaved dahlias need sunshine to bring out their vibrant shades