Q: Against my landscapers opinion I had him install about a dozen Leyland Cypress trees along the side of my house. He advised that they grew like weeds and would be hard to control. Was he ever right. Can you recommend a time and manner for trimming these beasts?
A: Rick Smith, owner of The Pruning Guru says you could try pruning the Leylands but eventually you’ll wish you had replaced them. Sunshine looks to be limited on your site and their bottom half will get thin and diseased under those conditions.
Depending on your screening needs, ‘Emerald Green’ or ‘American Pillar’ arborvitae might be better choices.
I have more screening options at Plants for Screening
You could even consider building a wire arbor and training an evergreen vine like Clematis armondii on it.