In message , Janet Baraclough
writes
The message
from Stewart Robert Hinsley contains these words:

I has another look at this a couple of days back, and it does indeed
seem to be Iris siberica (hollow stems).

Wonder if it was a garden escape or someone planted it. I think some
houseboat dwellers
beautify their moorings.

Janet

Some of the canalside plants are probably planted - there's one lock
that has Rhus typhina, Vinca major and Lathyrus tuberosus next to it,
but others, like this one, appear to be spontaneous.

Garden escapes do turn up in the oddest places. I know two places where
Sidalcea is growing "wild" (this is one of the sterile hybrids, so
presumably they're throwouts of some form) - one is near a fishing pond
on what I suspect was once industrial land, which I suspect arrived with
some thrown out topsoil (the locality also has Alchemilla mollis and
Lysimachia punctata), and the other is on top of a hill (the locality
also has the broad-leaved bluebell which may or may not be Hyacinthoides
hispanica). And I saw a sunflower in the middle of a potato field, and
another growing in a crack in a canal bridge, and a tomato in the middle
of a maize field. There also was a colony of potatoes growing in a
roadside verge (I haven't seen it this year).

But I'm still finding new genuinely wild plants, as well as garden
escapes. The latest discovery is Ornithopus perpusillus (a little
legume) found growing in mown grass along an exurban road.
--
Stewart Robert Hinsley