Also you have to consider the height of the hedge, so select the appropriate plants for the height you want your hedge to be. No hedge will stop at a certain height but some are easily to be maintained by regular pruning at certain height than others.
When starting a hedge you have to consider that you will need a lot of plants. You might find them less expensive between late autumn and spring as bare-rooted plants, of course you will also have to plant them during the dormant season. First soak the roots in tepid water for 8 hours to rehydrate the plants and put them into a patch of ground if they cannot be planted straight away. Some plants are only sold as container-grown plants, making a hedge quite expensive, but they have the advantage that they can be planted at most times of the year, except when the soil is frosty, muddy or during drought periods, when plants are difficult to establish.
No matter what kind of plant you choose for your hedge, but for better result consider that spring and autumn are the ideal planting times. Also consider that small plants represent the best value as they establish faster than large plants and grow rapidly to catch up with them.
Plant formal hedges in double rows, 40-45 cm apart with plants the same distance apart in the row but staggered to produce a dense, solid hedge quickly. Plant conifers and bushy shrubs in a single line 40-45 cm apart. Before planting dig a trench 1 meter wide and fork as much well-rotted organic matter or tree planting compost as possible into the bottom. Add general fertilizer and bonemeal into the soil before replacing it in the trench. Plant hedging plants in the same way as for normal garden shrubs.
Cut plants back hard after planting to avoid having a hedge that is bare at the base. Prune bare-rooted plants to 15 cm above ground and container-grown plants by one-third. Feed the plants in spring by scattering general fertilizer along each side of the hedge and water it well in. remove weeds regularly and mulch in spring, especially when the hedge is young.