Colour me happy: How to add a coordinated splash of colour to your garden

Understanding the way different hues work together is key to understanding the art of gardening. And it's a skill that requires fine tuning, says Emma Townshend.

You know right away when you've got the colours in a garden wrong. Here are just some wrong things from my personal album: the deep 1960s purple of an allium, making an adjacent rose in fine-toned pink just look ill; and what about two white flowers next to each other, one rendering the other the shade of the nicotine-stained ceiling of an unrevamped pub? Or finally, daffodils in spring, over-the-top yellow, drowning out the dreamy blue of camassias? Wrong, wrong, all wrong.

When people ask me cheerfully if I know "a lot" about gardening, I tend to say: "Nope." What is that? A sort of pathetic false modesty? A strong sense of how much more there is to learn? My continuing failure to have any kind of mastery over colour is the biggest thing on my mind when I deliver that answer in the negative. It's all very well knowing the names of plants, having a rough idea how to keep them alive, and maintaining an up-to-date rogues' gallery of possible animal assailants. It's just that I don't think I ever manage to make it all work together.

And to me, that's one of the hallmarks of someone who can actually say they know about gardening. Someone who has actually made a garden that works, over time, with colours that chime and tone and enhance. Instead of ones that make the owner of the garden sigh and make a face like a sad dog. A sad dog that needs a walk. (Whine.)

So two years ago, I decided to take a different tactic. The colour thing bothered me so much that I began to focus on it. I wanted colour to unite and enhance the garden. Most of all I wanted it to continue to work in my favour throughout the season, a puzzle not just in three but in four dimensions, as the gardener frowns over the changes that will occur as one plant finishes flowering and another takes its place.

First, I took a few tones that I really like – that vivid bright green provided by euphorbias, new leaves and fresh grass; plus a pure, undiluted pink. I created a sort of spine up and down the garden of these colours, putting in a Barbie-ish "Gertrude Jekyll" rose here, a lipstick Penstemon "Andenken an Friedrich Hahn" there. A ton of Valerian. The raspberry Clematis "Julia Correvon" was welcomed in with open arms and a large bag of fish-blood and bone plant food.

Just as importantly, the bullet was bitten on patches of colour that worked against the scheme. Out went a hardworking but idiotically placed red-hot poker, whose tepid orange and yellow were never going to help. Out went dirty reds, too, such as an undistinguished Phygelius, the Cape Fuchsia. Allowed to stay were all the crocosmias, whose heat was fiery enough to enhance the overall pinkness. And the famous Honeysuckle "Gold Flame" with its two-tone orange and pink flowers got a parking permit on the same basis.

And for the first time, by thinking carefully, screwing up my forehead over complicated flowering equations, and using lots of graph paper, I feel like I'm getting somewhere. Everything zings, instead of just drooping. And where two colours don't work, I've tried to link them together with another tone; a purple and an orange, bridged with a red. There are still mistakes. I think there will always be mistakes. But for the first time in 20 years, the colours are good. And I'm letting a very small smile on to my face about it. I may even consider modifying my answer to the question "So you know lots about gardening?" to: "A bit."

A harmonious quartet of pinks

1. Valerian

Grows in cottage walls and Chelsea show gardens with the same enthusiasm. And it will flower till October. £7.99 a pot

2. Penstemon 'Andenken An Friedrich Hahn'

"The best penstemon ever," says Val Bourne, Crocus's plant expert. Will flower till first frosts too. £7.99

3. Honeysuckle 'Gold Flame'

A pink star, orange orbits… like an advert for the first satellites in space. Flowering until August. £12.99

4. Clematis 'Julia Correvon'

A soft deep pink, with flowers that cover the plant in the right conditions. Flowers till November. £12.99

All crocus.co.uk