Q.Roots of a lemon tree
Will the roots of a lemon tree planted near a wall cause any problems?

Certified GKH Gardening Expert
They should not. Roots of most trees, lemons among them, are pretty lazy. They will grow where there is soil and don't like to force into things. Tree roots become a problem when the tree is lacking space or water. The roots then become aggressive and can get into pipes (looking for water) or push out walls (looking for space). As long as the side of the tree that is away from the wall is free from obstruction, it has plenty of space and will not push on the walls.