We rarely ask ourselves the question of the development of a plant when it is planted. Whether planted alone near a building or in a hedge, trees and shrubs must have enough space to grow and not cause any damage.
Trees with large development
Would you like to adorn the front of that old wall with the silhouette of a majestic tree? Be careful, some species will undoubtedly lend themselves to this, but others should be avoided. Let's take the simple image of an iceberg: the emerged surface represents only a part of the existing... For trees it is the same thing! Some of them develop a root system so important that it represents twice the volume of the foliage!
Generally speaking, plan to plant large trees such as oaks, plane trees, pines or cedars at a minimum distance of 10 meters from any concrete construction. Only trellised pear or apple trees and, of course, climbing plants will be able to adorn your old wall in complete safety.
Similarly, certain trees that produce suckers should be avoided near buildings, such as mahonia, locust trees or even certain poplars whose roots can slip under the structures.
Let's not forget either that a large tree weakened by a storm can become dangerous and that falling branches are not rare. Some trees are more susceptible than others. So never plant a walnut, a poplar, a eucalyptus or an ash tree, not far from a veranda or a roof.
The same goes for drains and septic tanks, which should always be kept away from future plantings because the roots looking for water could very well make them explode.
Medium-sized trees
The planting distance will be a little shorter for medium-sized trees such as the plane tree, the hornbeam or the Judas tree. For these plants, leave a space of 5 meters from a building. Beware of the fig tree, which under its harmless appearance, has intrusive roots that play on any masonry element with disconcerting efficiency.
Don't imagine that you can stop tree roots with anti-rhizome barriers like those used to control bamboo! Much deeper and more intrusive, tree roots will be totally insensitive to them. It is therefore better to respect the right distances.
Ornamental shrubs
Forsythia, lilac, seringat, buddleia and other weigleias are very appreciated for their decorative flowers. For them to grow well, leave a distance of 1.20m on all sides around the shrub so that it can benefit from both the light and the ventilation necessary for its good health. In beds, bush roses should be spaced 80 cm apart.
