Mike Lyle wrote:

It was suggested that the ragworts didn't colonise well-stocked
grassland, but I'm afraid they do, round here at any rate. How else do
they appear in lawns?

They appear in lawns, in my experience anyway, when the lawn is
getting a bit bare in dry weather. At least that's when the ragwort
establishes itself.

Ragwort in lawns is a total non-problem assuming it's not allowed to
flower which seems unlikely unless the lawn is really neglected! :-)

On our land it does actually appear on the lawn more often than in the
longer grassed (but fairly well maintained) orchard. I think this is
because the lawn is closer to overgrazed (and thus bare) pasture than
the rather grassy orchard.


The cinnabar moth won't be preserved by half a dozen plants in some
gardener's back hedge anyhow.

It certainly won't be preserved by plants on a lawn, the caterpillars
wouldn't find enough to eat and would probably get trodden on.

We do actually leave ragwort plants which are well infested with
cinnabar moth caterpillars on our land in spite of having horses. The
caterpillars prevent the plants from seeding and to my mind provide a
continuing biological control of the ragwort population.

--
Chris Green )