Posted: 19/06/2016 at 21:17
On average - and it greatly depends on the climate where you are - an established laurel will grow around 12 to 18 inches a year, sometimes more if the conditions are right, and as they mature, they'll often put on a good bit more than that.
If you buy them, don't make the mistake of thinking bigger is better. Bigger specimens are harder to get established. Around three feet is about the best size. They need room to grow out as well as up, as they're not the type of hedge you can clip tightly and keep narrow like Beech or Hornbeam. Remember that anything which grows quickly will also need a lot of pruning. Laurels can also become truly enormous if left to their own devices.
As you're replacing conifers, make sure you enrich the soil before planting anything else. Conifers take a huge amount of nutrition out of the soil. Manure, compost and a general feed dug in first. Keep the plants well watered till established. A mulch after watering is also beneficial.
Hope that's of some help