I had forgotten.

It's so long since I've seen/REALLY looked at a Wild Arum I can no longer tell if this is a "Wild Arum" or a tame one.
Be that as it may, I keep hearing the Gurus on "GQT" telling us how rampant & spreading they are.
Neither of us can remember seeing these, in next door's garden so can't tell their spreadability - YET.