Screening Trees: Options for Towns and Cities
By Lorraine Spooner
This week we are looking at options for screening trees for urban planting, focussing on pleached screens. This is a two-part blog, Part 2 next week, will detail options for screening with standard ornamental trees.
Careful research into choice of species is important when selecting plants for this location (compared to rural gardens and planting in the wider landscape), to eliminate any future problems that could occur if the wrong tree is chosen. It is not just visual appeal, but mature height and spread, growing requirements in terms of light levels, watering and maintenance, that need to be considered, to ensure a successful and long-lived outcome in achieving your screening goals.
There has been much media attention on the loss of trees in our towns and cities, which can partly be attributed to an overly cautious approach by insurers and councils. Urban tree planting is absolutely essential to maintain a healthy environment in built-up areas, especially for the people and animals that reside in them. By creating more privacy in your own space, you are contributing to greening our towns and cities for future generations to enjoy. Producing clean air for us to breathe, trees also remove pollutants that could otherwise contribute to health problems.
Concern is often expressed over the spread of a tree’s roots and the damage that these may cause to foundations, boundary walls or neighbouring properties. With the right plant chosen for the right place, this need not be a problem and by installing a root protection membrane at planting time, this will assist in restricting a root’s development and spread. However, soil type and soil structure should also be a consideration when making your choices. Gardens on chalk or sandy soils are less likely to cause problems than those on heavy clay, and the larger the tree, the higher the water uptake will be. Long hot summers can quickly cause soils to dry out, encouraging roots to seek out moisture beyond their natural canopy – this is known as ‘seasonal soil moisture deficit’, because the soil will have a chance to rewet following winter rains. Ensuring the correct watering regime will greatly assist in preventing potential problems arising. View the Nicholsons Planting and Watering Guidelines here for more information.
Consider the intended purpose of planting screening trees in your urban garden – perhaps you wish to create more privacy from a neighbouring property, or if your boundaries are roadside, to reduce noise levels.
The optimum recommendation must be pleached screens (pictured right) – this method of training young branches over a supporting framework provides instant impact and is often referred to as ‘a hedge on stilts’. The height of the clear stem can be tailor-made on some species to accommodate different fence and wall heights. Taking up minimum ground space, they are a good option where garden space is limited and here are some suggestions of trees in this form available to view on the Plant Centre.
Holm oak is a fast-growing, widely planted evergreen, tolerant of many garden aspects and environmental conditions, making it a versatile choice for screening purposes. The foliage is spiny when young, becoming smoother with age alluding to its popular name of holly oak.
Prunus laurocerasus ‘Novita’
This hardy and resilient cultivar of the cherry laurel has large, glossy, dark green leaves and ‘candles’ of cup-shaped, fragrant white flowers in spring, followed by red fruit which ripen to black. Also available in Prunus laurocerasus ‘Caucasica’ – the Caucasian laurel, whose foliage has a more lanceolate form.
Ilex ‘Nellie R. Stevens’
A hybrid between Ilex aquifolium and Ilex cornuta, this self-pollinating female holly is a tough evergreen with a dense habit and can be depended upon for an abundant crop of bright red berries in autumn/winter to satisfy your garden birds.
Our hardy native Hornbeam is a popular, semi-evergreen, choice for pleached screens, being more suited to clay soils than our native beech, Fagus sylvatica. The coppery tone of its autumn/winter foliage is a delight when the contrast of the bright green, young foliage peeps through in spring. Foliage retention is dependent on environmental conditions through the seasons and can vary from year to year.
The Oleaster is an evergreen with grey-green foliage, silvery underside, producing small, creamy white, scented flowers in the leaf axils in autumn with berries in the spring, giving unusual seasonal interest in reverse order! A good option for lightening areas if boundaries are in partial shade.
For those who prefer seasonal changes, deciduous pleached screens are also available in Malus, Liquidambar and Pyrus species.
There are many other choices not in stock which could be ordered on your behalf. Our Plant Centre is open with a full complement of expert horticulturalists on hand to assist you, Monday to Saturday, 08.30-16.30. Alternatively, I would be happy to advise further by e.mail firstname.lastname@example.org. We look forward to welcoming you soon.