Let’s be honest any roof, or high rise balcony, is never going to be the ideal place for a garden; they are frequently hit by high winds and they are usually either very hot or very cold. Nevertheless they are often the only space available for city dwellers and there have been some very famous and successful roof gardens created in the past and present. This said you will need a great deal of ingenuity and a burning wish to be surrounded by plants to even begin to make it a worthwhile to create a roof garden.

The first thing to consider, design wise,  is that whether you own a huge penthouse or a tiny balcony the biggest problem is always going to be the harsh conditions, limiting your plants to those that are used to growing in dry semi-desert or Mediterranean climates. Forget British native species such as moisture loving primroses, azaleas, foxgloves or hardy geraniums and you can certainly rule out anything like tender silver leaf herbaceous plants.

You may get away with growing them for a while but sooner or later they will capitulate to severe weather conditions. There is one bonus however about creating a roof garden; you aren’t likely to be in a frost pocket!
Before you even set about planning your elevated garden do be sure of three things. First of all you must check if the roof is strong enough to hold things like pots, soil or even paving. Next, make sure the access is suitable to lug heavy materials and plants up to the roof, or high balcony; a tiny or steep entrance point could eventually defeat you. Finally, in your enthusiasm don’t overlook the fact that you are going to need water in copious amounts, especially if the weather gets hot and dry.

Try to provide some shelter for you precious plants, preferably with a permeable screen that filters the wind rather than resisting it. This way you are less likely to watch your fence sky diving to the ground below. Also a wall may be stronger than a fence but it will create a great deal of turbulence that could make it nearly impossible to sit in the garden. A cheap and practical way of giving a remarkable degree of protection is to put up simple garden plastic netting, well secured, and then clothe it in hardy climbers.

To brighten up the floor of your roof top ‘paradise’ you can use gravel or stone chippings, decking or even artificial turf. Be careful about putting down masses of heavy paving slabs unless you are guaranteed that the roof structure will support them. Another way of giving this unusual outdoor space some character is to create small cobbled circles or paths that focus on beautiful central pots or planters; spilling out masses of brightly coloured flowers.

If you want to sit in your garden on still warm days you should choose something like a very solid wooden bench rather than a lightweight aluminium chair, since the latter could well become airborne in a strong wind. The alternative is to invest in a heavy picnic bench, which isn’t really going to go anywhere and is a great place to enjoy a cup of coffee, eat alfresco or even, on sunny days, work on a computer.

Plants for a roof garden are of course limited, but some that are well worth trying are old favourites like roses, clematis, honeysuckle, jasmine, dwarf blue leafed conifers, yuccas, potentilla, gorse, cistus, low growing broom and lots of tough annuals or bedding out plants. Use your common sense about the plants you select and be prepared to stump up for regular replacements. Roof gardening requires a rather different state of mind from that of your average, everyday gardener.