Can I Compost Conifer/Leylandii branches?(From the Garden waste category | 1 comment - join the conversation)
Like all plant matter, conifers, including Leylandii, can be composted but most people avoid adding them to their usual compost heap.
The branches and leaves are very acidic so can upset the balance of your compost heap and later, your soil. The resin can also be toxic, so be careful of that.
Even shredded into small pieces or run over by a lawnmower, conifers take ages and ages to rot down (three to five years isn’t uncommon). (Their acidity and their rubbery leaves make it difficult for composting bacteria to do their magic.)
If you’ve got a lot to get rid of (and if you’ve got leylandii trees, that’s very possible), consider starting a special slow compost heap to avoid interfering with the speed of your normal one. Or find another use for them: some people take advantage of their slow-rotting nature and sprinkle them on muddy garden paths.
Alternatively, you can use your council’s local green waste recycling service to get rid of them: they might be unsuitable for a basic compost heap but industrial composting processes can deal with them much more successfully.