Q When should I trim my leylandii hedge?

Bruce Cummings, by email

AMATT SAYS Leylandii or Leyland cypress (× Cuprocyparis leylandii) makes a vigorous, dense hedge that needs trimming at least three times a year, from late March (before birds start nesting) to late September. The cuts need time to dry out and heal before winter, so they’re not damaged by frost.

Give leylandii its first trim of the year before the birds start nesting