Q: Our back garden is overlooked from the upstairs windows of the house at the end of the garden. What trees could we consider to provide privacy?
A: You are probably asking this question on behalf of many others and there are a number of things to consider in making the right choice.
Firstly, how quickly you are prepared to wait for the privacy to take effect?
Secondly, whether you need year round privacy or just during the spring and summer when the garden is more likely to be used?
Thirdly, whether the new found privacy will on the other hand create more shade, either for you or your neighbour?
Fourth, if you will need to maintain the trees at a set height or if they can grow up indefinitely?
And fifth, relating to both previous considerations is an awareness of the law. Be aware of High Hedge legislation which could enable a neighbour to take action against you if you allow planting to cause detriment to their property.
Tying together all these factors, the first point to make is that the quickest growing trees will be the cheapest way of gaining quick privacy but will require more maintenance or become problematic going forwards. Therefore I would strongly suggest that both the infamous Leylandii (X Cupressus leylandii) conifers and eucalyptus trees can become monsters and should be avoided at all costs.
A conifer compromise might be Thuja plicata which if maintained well is a manageable and good looking screen. These like most conifers are evergreen and will give year round screening.
Other evergreen trees which could be considered are Acacia dealbata, which is quick growing and produces yellow flowers in winter, but it has a spreading habit and will need pruning to contain it. Also the often overlooked or perhaps unfashionable Cotoneaster Cornubia which comes with the bonus of clusters of red berries.
If you like the idea of evergreen trees with a clear stem such that the “head” is above the fence, nurseries offer this style and the most commonly available species are probably Photinia Red Robin, Prunus lusitanica and Eleagnus ebbingeii. These are not cheap but can provide a fairly quick fix.
If you do not need year round privacy, deciduous trees offer far more variety and will normally be much cheaper for providing an instant result. It is obviously still important to choose the right species for the size of your garden, and for most moderately sized London gardens it will be best to choose trees with an upright habit to avoid unneeded spread and overhang. Possibilities are Acer Rubrum “Scanlon” (great autumn colour), Carpinus betulus “fastigiata” (a hornbeam with dense foliage) and Craetagus monogyna stricta (a hawthorn with white fragrant flowers)
Infact deciduous trees can offer some screening even during the winter depending on the density and habit of their canopy.
Bamboo is another option available from some plant nurseries at an initial height of 3 – 4 metres. It is very advisable to install bamboo root barrier as even the apparently “non-invasive” clump forming bamboos do seem to have ambitions to increase their territory.
One final thought is that securing your own privacy might rob you of the opportunity to snoop on your neighbours from your upstairs windows!