|Frontenac, Peter Avenue|
Update: Two suggestions so far: 1. Triffids. 2. Acanthus (x 5). 3. Delphinium.
I think, a la Eurovision voting, only Acanthus can now win. Thanks to everyone on Facebook and Twitter.
From Mordell Gardens: "Acanthus mollis (or spinosa - need to see leaf to check)". From American friends: They are also called "bear's britches".