Why You Should Not Plant Leyland Cypress!:
This rapidly-growing tree quickly outgrows its space in a typical yard unless properly and regularly trimmed. Leyland cypress only lives for twenty to twenty-five years. I've found that trees left to grow large may have limited root support and are the first to blow down during high winds. You should consider the work needed to maintain a Leyland cypress before planting.
Leyland cypress is also very susceptable to seiridium canker.
Leyland Cypress and Seiridium Canker
*Leyland cypress is a handsome plant with Christmas tree-like qualities.
*Leyland cypress can put on three feet of growth per year on a good site. "More Bad Trees"
More Info on Leyland Cypress: