About five years ago, my neighbour had a group of the above seriously
trimmed, and gave me a large pile of chippings which have sat against a
wall in my garden ever since. Investigating that pile recently, I find
a lot of the chippings have broken down to a very friable condition.

However, said pile is also a mass of roots, which have grown up from the
trees next door. I have pulled out the larger roots, but there are
bound to be smaller lengths remaining. Were I to use that material as
mulch, or just dug into my garden, are the roots likely to die and rot,
or am I likely to be cursed with a million little horse chestnut trees
popping up for the rest of my life?

--
Graeme