They take 2-3 years to settle in and grow. You should see some growth this year. Did you enrich the soil before planting and is the soil not compacted? You also need to keep watered this year.

That soil looks to be very poor quality, as Botanic has already asked ddi you enrich?

hate the leylandii worst things ever to be given space burn them...sorry but that how i feel about these horrible plants

I set my 5 leylandii one year ago when they were 4 ft tall. 3 of them are now over 7 ft but they 're very skinny.
I hope they'll thicken out soon.

Hank try cutting the tops off - sometimes makes them bush out.

Yes keep them cut back to no more than 6 foot.

YAY - I've done something right ! I cut the tops off 3 of them the other day as they'd reached the required height, hoping I was right in doing so. So thanks the last 2 replies which quite made my day.

Thanks for replies. I did mix bonemeal with compost and soil where I planted. Will add more bonemeal. I have willows growing well nearby.

Best not to add more bonemeal now if you added it at planting.It is only applied every two or three years if needed, and then it is dug in during autumn and winter, apart from what can be added at planting time. It is slow release and will still be doing its stuff. The trees will still be making roots and you should not expect much growth this year. Just keep the ground moist but not soggy and let them get on with it. Too much bonemeal is worse than not enough and can burn the plants, and leylandii are so vigorous once established that you will be trying to discourage them rather than get them to grow.

If you ever have cause to replace them try to choose a variety which is less of a menace.