Gardening: Insider dealing

Why do we arrange our window boxes so that casual passers-by get the best view? Emma Townshend orders an about face

At the moment I'm doing some serious rethinking of my house and garden. The first thing to change was getting new windows. Though it sounds totally over the top, I honestly feel it has changed my life. After more than a decade, I finally have windows I can open. The fitters, Graham and Dave, couldn't have been more pleasant to have around, arriving with their own massive tub of babywipes and a long piece of protective carpet for the hall. And they totally indulged me on the subject of plants, twisting the wisteria buds back into the main stem so they didn't break them while they were sealing the new windows in.

Now that I have openable windows, I can stick my head out and chat to my neighbours, watch the general life of the street and have a bit of breeze on a hot day. But most importantly, and something I'd forgotten would be possible, I can now have window boxes.

The window box is one of the great pleasures of English urban life, giving the chance to garden in bright colour all the way up to the front of the house. Cyclamen, sage and ivy will create a smart Chelsea effect, while trailing fuchsias, patio verbenas and busy Lizzies mark you out as more of a potential pub landlady. However, existing window-box philosophy agrees on one thing: the point is to garden for the people outside the house, not the ones inside.

I can't help feeling that's getting it all wrong. Surely it's the people inside, namely us, who do all the hard work. I only see my own house from the outside for the brief time it takes to stagger in with shopping. I spend considerably longer each day staring out, even if it's just while I'm getting ready in the morning.

So I wanted a window box designed to be seen from the inside out. Instead of the usual bright blooms, which would turn their heads away from the house towards the sun, I was thinking about sedums and sempervirums. Their tiny detailed structures reward repeated looking – the perfect thing to do while I'm upstairs drying my hair.

These make a wonderful display all summer long without needing feeding or much water. Conventional window-box advice will tell you to add water-retaining granules to the soil, but sedums are much too tough to require that kind of nannying, and survive beautifully on just what the rain provides.

By leaving a lot of space between the plants to be filled up with fine grey Cornish stones, I can have a calm Japanese sense of order in my window boxes. Lying in bed in the mornings, I can gaze out on a tiny Zen garden. I've added some baby agaves I was growing on in pots, for a bit of extra height and texture, and a couple of small new varieties of hebe, such as "Clear Skies". I couldn't resist a pink-grey hellebore, H.lividus, too. And for a flourish the central box is going to have a grass, Carex testacea.

To complete the Zen effect, I wanted the boxes themselves to be dark-grey metal or stone. For the posh end of the window-box market there are now good online suppliers (try www.theurbangarden.co.uk). I decided against galvanised metal, fearing it would heat up and cook the roots of my plants. In the end I spent what felt like millions on polished granite planters from Iota (www.iotagarden.com). The disadvantage of these is that they are astronomically heavy, about the weight of a small dark star. But they have a fantastic air of hotel opulence.

They may yet snap my windowsills, though, and if you are at all concerned about weight, granite planters are not for you. (I put the smaller trough on the bathroom scales and it added up to almost five stone – and that's empty.) If there is any chance it could fall on someone's head, you must opt for something safer. You may ask why I don't put the posh new window boxes on the ground-floor sills: well, we've had enough containers pinched in this street for me to decide not to leave my treasured creations anywhere accessible. Plastic flowerpots of landlady flowers will do for downstairs. Upstairs, though, I can gaze out on to my idea of five-star luxury. n

Get the look

Hebe carnea variegata 'Veronica'
Gorgeous grey-green leaves with a smart strip of white. Pink flowers emerge in May

Sempervirum
Try "Hayling" for rich reds, or "Hey-Hey" for greeny rosettes with a plum blush

Carex testacea
Olive-green foliage that will turn a stylish bronze. Has a good, soft, cascading shape

Sedum glaucophyllum
A rosette-forming, low-growing plant, it will form a dense mat of succulent whirls

Echeveria peacockii
Grey leaves, orange and pink flowers