Roof form trees also known as roof shape, roof top, umbrella or parasol trees are single stemmed trees that have had their central leaders cut away to leave a crown. The remaining lateral branches are then trained over a bamboo or steel frame to create a horizontal screen, creating an umbrella or parasol effect.
Roof form trees are fast emerging as a very popular choice to add structure and create natural garden architecture. Clients tend to use roof form trees instead of pergolas and arbors to offer cool shade in the summer months. As living structures, they offer year-round interest by constantly changing through the seasons. In situations where small courtyard or town gardens are overlooked from a higher vantage point, they offer privacy to those seated beneath them. Unlike timber products which deteriorate over time, trees are living structures which improve with age. Deciduous trees are the most popular, as they allow light to pass through in the winter, while offering cover in the summer. Roof form trees are typically planted in a square or rectangular pattern. The stem heights start at around 230 centimetres, which allows good head clearance below the canopy.
Ideally suited to being placed on terraces or areas reasonably close to the house, where outdoor furniture, including dining tables can be placed below them. The natural cover created by the branches and foliage creates a classy, upmarket feel and dining experience. Up lights are regularly used to illuminate the trees at night. In the winter months while in the comfort of a warm home, lighting can be used to illuminate the bare stems and the canopies of deciduous parasol trees to great effect.
Much like our box head and pleached trees, our roof form trees are available in several different species. Some of the popular varieties include: Plane - Platanus orientalis 'Minaret', Pin oak or Swamp Spanish oak - Quercus palustris, Sweet gum - Liquidambar styr. 'Silver King', Liquidambar styr. 'Palo Alto', Liquidambar styr. 'Worplesdon', Liquidambar styraciflua, Plane - Platanus 'Alphen's Globe', Platanus hispanica 'Malburg', Hornbeam - Carpinus betulus, Crab apple - Malus 'Evereste', Mulberry - Morus alba 'Macrophylla', Pear - Pyrus calleryana 'Chanticleer', Lime - Tilia europaea 'Pallida', Evergreen oak - Quercus Ilex.
Due to the cubed/square structure of the “roof”, roof top trees typically look at their best from an architectural point of view when planted in lines or squares. This being the case it is important to make sure the stems line up, the heads are at a similar height and they are square. Machinery is required to plant all but the very smallest of the trees we supply so taking time to plan will save time and money in the long run.
Maintaining parasol trees is relatively straight forward. All you need is a sturdy platform with the necessary support, a sharp pair of secateurs, loppers, safety glasses and appropriate gloves which are availabkle from Felco, our preferred brand. The aim is to clip lightly once or twice during the growing season to retain the shape of the crown and a sense of order. Once a season – timing dependent on species, the aim is to prune back the previous year’s growth, leaving the original leaders in place. Over time these leaders can be left to grow to the desired length. Once the canopy is the correct size it can be maintained as such by clipping back each season – easy!
Some species such as Limes, Mulberries and Planes for example enjoy being managed heavily where only the main leaders remain at the end of each season. Carpinus or Hornbeam on the other hand look better left with a dense network of branches. The species of tree you choose will determine the pruning method.
We supply detailed feed and watering instructions with all orders. While failures are rare, they tend to be down to a lack of water and in very rare cases to much water. It is therefore important to implement a strict watering regime once the trees are planted and to monitor soil conditions closely. Plants will benefit from a seasonal feed and therefore application of organic or manufactured feed. General purpose granular fertilisers such as Osmocoat are good for this purpose.
Roof top trees are particularly popular on the continent and this seems to be rubbing off on homeowners back home. In Zurich Switzerland for example parasol/umbrella trees can be regularly found at tram stations around lake Zurich (Zürichsee), offering passengers welcomed shade in the summer months. All along the south coast of France, roof form trees can be found at private residences overlooking the Mediterranean. Plane trees (that don’t normally enjoy sea side locations) have been planted in small private harbours meters from the sea and they are thriving.
Roof top or parasol trees are extremely versatile and while still not as common in the UK as on the continent, they are catching on. From young trees to the largest mature trees available in Europe we will help you find the tree that best suit your plans. Please contact us for more details.