Evergreen conifers such as Cupresssocyparis x leylandii (Leyland) are great fast growing plant with thick foliage which can work well if pruned regularly. Thuja plicata (Western Red Cedar) is a great alternative that you can trim back hard if necessary and it will still regrow
Alternative evergreen choices such as Photinia Red Robin and Prunus Lusitanica (Portuguese laurel) are non-conifer evergreens that can achieve a total 5-6m in height, they are hardy and popular hedge plants but also grow as standard trees.
Other non-conifer evergreens include: Laurus nobilis (Bay), Ilex (Holly) – a hardy and wind tolerant tree, Arbutus unedo (Strawberry Tree)and Cotoneaster cornubia (Semi-evergreen).
Any tree will help to screen an eyesore behind it, give a bit of privacy or provide a focal distraction.
The advantage of using deciduous trees for screening is that there is a lot more variety available. Many of these trees grow quickly, and add foliage, flower and fruit interest.
Although they lose their leaves, some deciduous trees and hedges have screening advantages. For example, trees that keep their leaves well into autumn such as Crataegus lavallei and Pyrus Chanticleer still give screening in the garden during sunny autumn days. Other trees with well-branched crowns such as Crataegus – hawthorns and Amelanchiers provide cover during summer months when you are most likely to be in the garden. Remember that deciduous trees give some filtered screening even without leaves and let light in during darker months.
A more formal alternative is Pleached or Panelled trees. They take up little room, where space is at a premium and form a good barrier in summer and winter. Typically supplied on a bamboo framework, and having the effect of a hedge on stilts, these are perfect for above-fence screening in restricted spaces. Tilia species, Carpinus and Photinias are popular and functional choices.
Hedges are also often used to provide a solid screen from large or unattractive nearby buildings- such as car parks, caravan sites, housing developments, farm buildings or other developments. It is often best to choose species that grow well in your particular area to ensure they will blend in with the environment.