Question
Could you give me some idea of the root spread of Leylandii; I have a 20 feet hedge within about 6 feet of my house, nearer in some instances.

Answer
Most of the roots system is in the upper 2 feet on surface soil. It may spread out to about 2 times the size of the crown foliage area. There should be no problem with the foundation of the house from the roots. BUT at maturity it is a pyramidal tree, to 30-40 feet tall and 25 to 30 feet wide. The branches will be rubbing on the house if it is 6 feet from the house. The branches can be kept off the house with pruning the ones back on the house side.