However modest your space, you can still cultivate a little patch of heaven

Garden design books often spend a lot of time stressing the importance of using borrowed landscape, blurring the boundaries of your plot or creating hidden corners.

But if your garden consists of a small patio surrounded by buildings, you're going to need a very different approach. In urban areas, small, enclosed gardens have always existed in order to offer a sanctuary from noise and pollution (or to house the privy). Often they're concreted over and used as a dumping ground for bikes and bins, but no matter what the size of the space, they've got potential to be transformed into little green oases.

Jenny Hendy is co-author with Joan Clifton of a new book, The Complete Practical Guide To Patio, Terrace, Backyard & Courtyard Gardening (16.99, Lorenz Books). She says that the cosy nature of these spaces is actually something to be celebrated rather than pining for a grand vista. "As human beings we like to have some security around us - you don't want to sit in a field with your back to open space," she says. "It's nice to have a little bolthole where you've got walls or trellis around you and where you can get away from it all."

If your back garden has become a dumping ground, a simple spring clean can make a big difference. Clearing out the rubbish, followed by cleaning, weeding and pruning will reveal the basics of what you've got to work with. "There are tricks to make a very small courtyard feel bigger, but with courtyards it's more to do with making the space as interesting and engaging as possible and bringing light into the space as well," says Hendy. "Sometimes you might have high walls with very little light coming in, a concrete floor and no possibility of actually planting things in the ground. I look at that and think of it as a blank canvas, there's so much you could do." She says that one technique is to paint the exterior of the house up to first-floor level as that will concentrate your attention on the space at hand, helping you forget about what's looming above. Use a paler coloured masonry paint and you'll also be bringing in more light.

The book contains all sorts of practical suggestions for upgrading your site. If you have a mismatched selection of boundary surfaces, you could cover them with a roll of brushwood or bamboo screening, quickly attached to existing fencing using a heavy-duty staple gun. Trellis panels are another obvious choice, allowing you to grow climbers up them. To improve the garden floor, have the space paved or covered with gravel or decking to hide mismatched surfaces.An alternative is to clean existing paving with a pressure washer to get ride of the surface grime and algae then fill in gaps with bricks, setts or cobbles to add interest. "I think flooring is an under-rated element in terms of transforming a space," says Hendy. "It's a bit like laying carpet or some gorgeous tiles or wooden floorboards in your house - as soon as you do that you've got a completely different feel to the space than you had when it was concrete."

You might have a particular design style you want to go for, and the book has six specific chapters which look at how to create a traditional Mediterranean, productive, contemplative, modern or outdoor room-focused space. Hendy says that you don't have to be a slave to one particular style and that there's plenty of overlap between the themes. A traditional, formal courtyard might take inspiration from the medieval period and feature a stone fountain, herbs and old-fashioned blooms such as musk roses, violets, hollyhocks, larkspur, monkshood and foxgloves. Or if it's Italian Renaissance style you're after, you'll want large terracotta pots with bay trees, low-clipped box hedged, architectural plants such as cordyline, and mellow-coloured gravel. At the other end of the scale, if your name is still on an allotment waiting list and you want to grow your own, you can plant all kinds of edibles in large pots, troughs and hanging baskets. A relaxed space with beds edged with herbs tumbling onto gravel paths, plus traditional cottage garden plants such as hollyhocks, lupins and roses can create a countrified, natural garden.

Containers are a popular choice for courtyard gardens, allowing you to move things around depending on what's looking its best and to frequently change your display. Opting for plants that don't need daily watering is a good idea, or you could set up a mini irrigation system. When space is limited, it's important to think about the vertical element of your garden. Jenny Hendy suggests going beyond climbing shrubs and perennials and thinking about using topiary, clematis on pillars or small trees. "There's a tendency when you've got a small space to use very small containers and keep everything low level," she says. "Actually, if you look at a pot and think I'll have one ten times larger and have fewer of them, and in the middle of that space I'm going to have a tree, if you think in that way, you escape the boundaries and end up doing something far more dynamic and interesting."

The other good thing about having vertical greenery is that it cools the space and brings in lots of birds and insects. "It's quite extraordinary when you look at a space that's gardened like that then you pop your head over the wall and look at maybe a barren, concrete landscape next door," says Hendy."The atmosphere is so different, partly because of the wildlife you're bringing in." So if you've got a small, courtyard garden that's looking a little unloved, why not seize the bull by the horns and give it a revamp? "The more you live in an urban environment, the more you crave that connection with nature," says Hendy. "I think that's what's so lovely about making the most of these spaces and making them a place that's plant friendly."