tree/plant coverage to boundary
By Sweetman
United Kingdom 
We have recently undergone extensive home and garden renovation which has resulted in three laylandi trees being removed between ourselves and our neighbours. Subsequently we are in a gold fish bowl! Can you recommend plants or trees which will grow to approx 18 foot without overtaking or dominating our newly planted flower beds. the area for planting is north facing.
18 Jun, 2008
Answers
18' is very tall and will cast a LOT of shade. You'd have to plant shade loving plants in your flowerbeds. Do you know if your soil is acid or alkaline? I would think about flowering shrubs to add interest: if your soil is acid, there are Camellias which grow quite tall (not 18' though) Pieris, larger Skimmias and Rhododendrons. There are lots of interesting conifers but I am concerned that they might be as bad as your late-lamented Leylandii in taking over. I reckon a trellis would be a good compromise with perhaps scented evergreen Loniceras on it. But you live there and only you know the situation.
20 Jun, 2008
Spritzhenry and others can give you specific plants/trees. I just wanted to address a mistake I made - planted deciduous trees for privacy, and in the Fall lost all privacy..... maybe go for evergreens. I resorted to trellis and vines - a lower profile against the house. If that is an option for you for a bottom story, it is fast and economical while other things grow.
18 Jun, 2008