In message , K
writes
Do you mean the little pink one or the big white one?

The little pink one is field bindweed (Convolvulus arvensis), so I
presume that's what Nick means.. The big white one is large bindweed
(Calystegia silvatica). The less big white one is hedge bindweed
(Calystegia sepium). The big pink one is hairy bindweed (Calystegia
pulchra). The very little whitish one is black bindweed (Fallopia
convolvulus), a relative of Japanese knotweed.

The little pink one seems to like relatively light dryish soil., the
big white one is happiest when it has something to climb up.

It may be that much of the soil round here is too heavy for field
bindweed - there's a lot of boulder clay about.
--
Stewart Robert Hinsley