When you cut back your Leylandii too far, what can you do?

All hedges need to be trimmed once a year, twice if possible.  If kept to a reasonable height your hedge it shouldn't take long with sharp shears or electric hedge trimmer.

Always cut back only as far as green growth on the sides of the hedge, never cut back into the brown wood, as Leylandii will not re-grow fronds (leaves) from wood.

To contain and control your Leylandii keep your  hedge trimmed from the start and you trim it back once a year to the same size.  If the Leylandii trees are too over-grown or have lost foliage near the ground. The best thing to do is to dig them out, then start again, however large plants do get substantial roots.

Good news, there are cheats
Firstly, if you have room you could plant another hedge in front.

If the patch is small, brush or pull out the dead twigs or old wood and wait for the live stuff around to grow into the area, it could take some time but mature plants can grow 75 to 90cm per year.

Alternately, you could plant some ivy in front if you have patches to fill in, see image below. Ivy will grow in most any conditions, in full or little sunlight. We stock two types of ivy - Hedera Helix and Hedera hibernica.

Little hope for this one, how not to cut them back, you'll never get growth on that area.
Little hope for this one, how not to cut them back, you'll never get growth on that area.
Ivy as a filler for dead areas of hedging
Ivy as a filler for dead areas of hedging