Tall nettles

Tall nettles cover up, as they have done
These many springs, the rusty harrow, the plough,
Long worn out, and the roller made of stone :
Only the elm butt tops the nettles now.

This corner of the farmyard I like most :
As well as any bloom upon a flower
I like the dust on the nettles, never lost
Except to prove the sweetness of a shower.

Edward Thomas

I remember learning this poem at school, by yet another poet killed in the Great War.
These tall nettles are in the town centre. For some reason the council seems to think that if you put a mural on an empty building, it looks less empty. I think this one is meant to represent life in the early twentieth century, but I'm baffled by the obect on the left. It looks like a speed camera to me. Any ideas anyone ?