The secret is to grow climbers to scale walls and structures. Honeysuckle, clematis and climbing roses make good perennial choices anywhere in the country. If you live on the coast or in a low-lying, sheltered spot, you may get away with a more tender wisteria. Sweet peas are classic annuals and there are plenty of annual vegetables, such as runner beans and climbing peas: choose varieties with attractive flowers. Many soft and hard fruit species can also be trained to the height you want against a wall or a small fence.
Garden centres and catalogues provide many strong ideas for plant structures, but buy with care - if you're splashing out, get a robust specimen: flimsy structures please the pocket but not the plants. You'll find this especially true with arches and pergolas, as cheap ones simply sway in the wind and collapse under the weight of your cherished rose. Summer and autumn are the riskiest times, when plants are in full leaf.
Believe it or not, you can buy a rose arch for less than a tenner, but the metal is thin and joins are inadequate. More robust structures are made from non-corrosive aluminium, and while these more durable structures cost upwards of £80 they are a worthwhile investment.
Good aluminium arches usually carry a 10-year warranty, but some rustic wooden designs may be guaranteed for an additional five years. There are many attractive designs but, from an environmental point of view, go for one made from FSC (Forest Stewardship Council) timber. There's a risk unmarked wood may have been plundered from a tropical rainforest.
The FSC was established as a non-governmental organisation in 1994 after foresters, the timber industry, and environmental organisations grew seriously concerned about the relentless and unscrupulous destruction of irreplaceable forests. The aim was to certify timber extracted from sustainably managed forests in countries with good human rights records. Most Scottish forests are FSC certified, so you can buy local.
Metal frames or ones made with FSC timber make excellent focal points at the corner or in the middle of a bed. Wigwam frames are fairly sturdy and the most commonly available. Sadly, though, they're not plant-friendly. Once plants have scaled a structure, they meet at the top and inevitably smother each other. This dense tangle of vegetation is a magnet to any passing fungal disease. A much better alternative is an open-topped square bean frame made of aluminium. At £50 it's expensive, but it's durable and ideal for climbers. Round-topped obelisks are attractive but pricier alternatives.
Fruit hedges are greatly underrated. A post and wire fence to fit the available space makes a perfect frame to train soft fruit in whatever design you fancy - cordon, espalier or fan. It would need to be at least 1m high, but 1.5m would make the perfect wall for a little garden room. This also makes a good support for apples, pears and a wide selection of soft fruit - gooseberries, currants, tayberries or whatever you fancy.
And remember to take advantage of a south or west-facing house wall. Plaster the sun-soaked wall with your favourite climbers. If you don't have a bed, sweet peas do beautifully in a patio pot, as do runner beans and tall peas, trained against the wall.