On 24/09/2019 14:52, Jeff Layman wrote:
On 24/09/19 12:31, Martin Brown wrote:
On 24/09/2019 12:24, Jeff Layman wrote:

TBH I'm a bit surprised that it is in this list. It survives OK on my
clay soil but daffodils and narcissi are both more invasive.

Some daffs do seem a bit "vigorous", but they don't spread in the way
that Montbretia does.

They spread by cormlets, and sometimes by seed. In my experience, even
glyphosate has difficulty killing them (as it does with many plants
which have a storage organ such as a bulb, e.g. Spanish Bluebell). If
your neighbour still has them, keep an eye out for the leaves suddenly
appearing in your garden. :-(

I have never seen it escape from gardens around here. Daffodils do!

I don't know where you are, but I would guess anywhere south of a line
from Bristol to London would be fair game for Montbretia, and I think
that is why it has appeared in the CWA (see Chris Hogg's post).

North Yorkshire on heavy clay soil. Wet in winter which they don't like.

--
Regards,
Martin Brown