Our neighbour recently removed the 40′ leylandii on the north side of our garden, replacing them with a handsome 6′ timber fence. This has opened up a strip of garden at least 12′ wide, front and back of the house. What can we plant in it, given that the roots will still be there? We understand leylandii create a very acid soil, and were thinking of rhododendrons, azaleas, heathers etc.
You can plant anything you like into the ground newly available. Simply plant between big roots if necessary and the plants with no difficulty or competition from the felled trees. The shrubs you mention would be fine but you do not need to choose only acid-soil plants.