Border patrol: It's time to cut back on your 10ft-wide patch

There was a time when Emma Townshend would buy on impulse the sort of plants that wouldn’t look out of place in a National Trust garden. No more!

When I first owned a garden, I bought plants as if it were highly likely that my 10ft-wide plot would at some point concertina out into full National Trust-size double herbaceous borders. Nice big fat borders with glorious exotics such as honey spurge, plus a huge helping of English cottage-garden varieties. I'm not exactly sure how I thought this process would take place. Now that I've read a few Ben Aaronovitch books – in which ghostly metropolitan magic achieves all kinds of wonders in the grubbiest bits of London – I realise that probably it would have to have involved some form of sorcery.

But in the continued absence of enchanted policemen with conjuring powers, I have slowly faced the fact that I will never be able to grow all the things I want at once. There's not enough room. Not even slightly. And plants, being living things, tend to expand to take up whatever space you give them.

Plus, I don't always buy the right things. My front garden is mostly composed of plants I have wisely chosen for their excellent horticultural properties. But there is one sizeable purple hebe that I just felt sorry for one rainy early 1990s afternoon in B&Q. It was planted in a container the size of a Pot Noodle and had lost almost all its leaves, and I just thought I was taking it home to die comfortably. Twenty years later, it's the dimensions of a small coffee table and still produces a huge crop of flowers in that "difficult" mauve whenever it can be bothered.

Yet, even with a gigantic garden, life wouldn't become totally simple. Some of the loveliest plants are just too hard to keep alive. Local circumstances (practically biblical quantity of slugs and snails) dictate that the late-summer members of the daisy family, such as heleniums or echinacea, don't survive long enough to put up their gorgeous, bronzy heads. And when I make the effort to grow my own lettuces, it is almost unbearable actually to eat them.

So there are lots of things I've given up on growing. In truth, giving up on growing things is starting to become a form of spiritual discipline around my way. It requires enormous willpower to resist lovely roses at the garden centre, especially after you inhale enough of their perfume. "Buy me," they whisper, "I would look so very lovely winding my way around your rose arbor." It is at this point that I have to sternly remind myself that I don't have a rose arbor.

I've lately prevented myself buying plenty of shrubs that will grow semi-gigantic, and vetoed several small to medium-sized trees.

Using Zen techniques to calm the mind, I have also managed to avoid reaching out my greedy little hand for things in colours that don't actually work with anything else in the garden (bright yellow, obviously); things that require conditions I don't have (no more passion flowers, ever); things that refuse to flower except for a single week a year (the gorgeous but totally temporary camassia); and things with nice flowers but horrible leaves (sayonara, ceanothus).

The plants that are left are now hopefully guided by two important principles. One is that they have to go with everything else. The other is that they have to look good for most of the year. There are no National Trust borders. But there's still a bit left of the original dream: a grand, easygoing, unneedy of watering, most satisfying of greens, and genuinely real-life useful plant, whether in a grand border or not: honey spurge, I salute you.

Three to try

For an easy-care grand garden feel in an instant…

KNEE-HIGH: SALVIA GREGGI I ‘LIPSTICK’

A coral burst from Texas that will cheer up the autumn garden wherever you are. £5.99 at crocus.co.uk

MEDIUM-LARGE: FATSIA JAPONICA

Flowering now, even in deep shade, Fatsia is a tolerant, glorious thing with full houseplant levels of leaf shine. A huge five-litre plant is £24.99 at crocus.co.uk

GENIUNELY BIG: PHYLLOSTACHYS NIGRA

Black bamboo is stylish on a grand scale, but still serene in growth. A minimalist fave. £22.99 at crocus.co.uk