Jaques d'Alltrades wrote:

The message
from "nambucca" contains these words:

Since Leylandii strip the ground of nutrients i would not have left the
roots in ..........when i removed some i painstakingly cleared out the soil
around every root and got them out .......then i was able to pile in tons of
compost and the new plantings soon got going

Theres no substitute for doing a proper job

Well, any 'tree surgeon' worth his salt would have offered (for a rather
larger fee, of course) to take the roots out as well - which is much
easier *BEFORE* they have been cut off at the base.

Although some people swear by stump grinders which I presume can take
out tree stumps left in this condition.

However, what's done is done. Compost or well-rotted manure can be
spread as a mulch and the worms will soon take it down into the topsoil.

I'd be inclined to drill a few big holes in it and load them with
ammonium sulphamate (tradename Rootout). It will make sure it doesn't
come back and encourage the fungi to get going by providing some extra
nitrogen. Once the rots have weakened it a bit you can dig them out.

Regards,
Martin Brown