Composting Leylandii

The miraculously fast growing Leylandii, a.k.a. the Leyland Cypress is the enemy of many a neighbour from hell as if neglected they can grow one metre in height within just a single year!  As you can imagine if you do have such a plant, you need to keep it regularly trimmed and this means you are going to generate literally tonnes of hedge clippings every year.

So the question which arises of course is can you compost leylandii branches and clippings?

Of course the answer is yes, its a natural plant so it will rot down and we have seen people produce nice compost successfully from this.

But alot of people seem to think its a problematic plant.  We were quite surprised to learn one experienced master composter advise another not to compost leyandii cuttings as they were  apparently “too acidic”.  This is not really an issue because composting bacteria can remain active is all but the most acidic conditions and the process of composting ultimately even if it starts out as a relatively acidic heap will return to neutral pH if aerated!

We would say to take care to ensure they are well shredded and only add in small amounts.  This is the biggest challenge with leylandii – even most hedges with frequent cuts can generate wheel barrows of waste. A large cutback results in many branches that are really hard to shred.

The other issue is that Leylandii and other evergreen material take a long time to decompose, over five years in some cases. In general they are very acidic and the leaves or needles tend to have an almost rubbery texture, which repels moisture penetration and microbial attack. Decomposition can be speeded up by shredding them or by running a lawnmower over them if the branches are not too thick. Large quantities which would fill a compost bin should perhaps be taken to the Councils Recycling Centres instead as they sent their green waste for industrial composting and this is more capable of processing such large quantities of robust material. 

So ultimately the answer depends on how patient you are and how much space you have for composting, if you are prepared to leave them long enough though, they will go and they will produce a nice compost.