These trees could almost be called a garden pest! Leylandii or Leyland Cypress is a fast growing tree and can reach 50 feet in 60 years. You will be familiar with Leylandii as the green/ yellowish evergreen trees, ubiquitously used to form hedges which can soon become unmanageable if not tamed by diligent gardeners. In some residential areas they have been banned because of their rapid growth, and many disputes have arisen between neighbours because of the nature of the trees to go out of control, block light and protrude into adjacent gardens.
Anyway, I have a back garden with a short Leylandii hedge
spanning the gap between a side gate and driveway gate. The hedge was
planted in the eighties, and in those days I trimmed it with a hand
shears, which of course has limited ability to cut branches thicker than
about 1/4 inch. Every year the trees put on new growth, becoming wider
in the process as the shears could only trim back soft growth. By the
time the trees had become 15 years old, they had reached a width of
about 4 feet. I had bought a hedge trimmer by then, however I also
discovered a serious disadvantage of many conifers, unlike deciduous
trees, they can't be heavily trimmed back to old growth as they don't
resprout. So the Leylandii have now reached a width of about 7
feet and are practically hollow inside!
My plan is to hollow the
trees out more on the inside. Yesterday I cut out as much top growth as
possible which was overhanging the hollow interior of the trees. Dead
branches were removed also. By opening up the inside, this lets more
light in and my plan is to plant lots of holly and laurel which can
grow in lower light conditions, inside this space. Eventually the holly and laurel will take over and
emerge from the inside of the trees (Sort of like a
gardening version of Alien!) at which point I will remove the host Leylandii.