On 24/09/19 14:50, Martin Brown wrote:
On 24/09/2019 14:45, Jeff Layman wrote:


FWIW, I took me five years to eradicate Montbretia in our previous
garden - and I had planted it without knowing what would happen! In our
new place which we moved into seven years ago a small patch of it was
already growing. I dug it out, but it came back, so I must have missed a
corm. I removed that, and a small plant appeared the next year. That
plant was removed, and for three years I didn't see it. This year, it
appeared again.

But in that respect it is no different to foxglove, poppy or teasel.
Once you have them in a garden they are pretty much there to stay.

There is a big difference between seed dispersal and vegetative spread.
With any annual/biennial, or even perennial which reproduces by seed all
you need do is deadhead for a couple of years (maybe more with poppies),
and you've eradicated 99% of the problem. Trying to get rid of anything
which spreads underground can be extremely difficult. I have a list of
plants I will never grow again because on previous occasions they have
spread uncontrollably by roots, rhizomes, or underground shoots.

I've never grown any of the plants you've mentioned, and I've seen them
in my garden only on very rare occasions, obviously blown in on the wind.

--

Jeff