My mate's got a huge lilac tree now shedding all its leaves.  He'd like to add them to his 'long-term' compost heap, 'cos the leaf bin is full and he doesn't want to bag them.Â
But he says he's heard somewhere that they shouldn't be composted. Anybody know what, if any, harm they might cause?  ???
Nope, nor me. My godmother believed lilac flowers indoors to be unlucky, but that's all I know about them!
The only thing I can think of about lilac leaves, is that extracts are thought to have some anti-bacterial qualities, something to do with phenylpropanoids and essential oils.
Following this thought process through, maybe it was considered that this prevented the necessary microbial action associated with composting?
In any case, I've put them on the compost heap with NO trouble.
Thanks for that, Jenny.  He was talking about putting them in black bags and hiding some in the wheelie bin every fortnight - no green waste collection around here :( - but much happier now.
My gran, bless her, used to put lilac leaves in the tin bath. Now I know why, akin to rosemary perhaps? Not all these old wives were daft were they?