What ditance to houses has tobe kept, so that the walls get not damaged by roots?
This question we will answer at the end. Because sometimes plants are sold that are estimated as slow-growing or dwarf-species. This promise is usually true, but to enjoy with caution. Some so called slow-growing plants will also be giant after a certain time. And such a 'slow-growing promise' says nothing about the roots !
That strange things might happen we will show you with the following extraordinary examples. Both are exceptions, but they demonstrate impressively, that with planting instructions the root growth may not be forgotten. So the question: "how far away of masonry or plaster surfaces may I plant, for example a hinoki cypress", can not be answered in general. You will see soon why.
The first case was a hinoki cypress of about 3 meters of height. A rather average copy, but the surprise was stuck in the ground. With an estimated age of about 15 years, it had developed a gigantic root. In order to be able to plant something new, we were ordered to dig them out 'quickly'. But what the owner did not know is that the effort was doubly meaningful. In the background, at the gray stone pedestal you see a yellow dot. And this marks (in Germany) the exact spot where the gas line is running into the house. Another few years of unhindered growth of the rootsmight have caused a cost "explosion" .
Example two is also a conifer. Possibly a Thuja or cypress, we don't know because a friendly neighbor had cut the tree before we have seen any branches. Unfortunately, he did it without expertise, because he had cut off the root so deep that you could not use it as a lever to pull out the root. Even with a 3.5 ton pickup truck we could not even loosen it.
The conseuquence was that the damaged paving had to be removed, and the roots had to be dug out in a wide area. Only then it was possible to use a chain saw. Thereafter, under destruction of various chains, the vertical taproot was cut. Since this type pavement was no longer produced we had to improvise. According to the unanimous opinion of the audience, it was the nicest solution.
So what is the answer to the question above?
As a general guide, one can say that the root area is not greater, than the crown diameter. Exceptions are the few deciduous trees thats roots can form new trees (see the article "Lilac" or the garden answer "What can I do against the root shoots of a Goldulme?") .
Conifers don't have this ability. Among those, however, is to ensure that they still receive enough light even after several years. Not only a hinoki cypress is misplaced in the distance to a house wall, the photos above show. Moreover, the rear gets brown automatically because it gets gets no light from the backside.