I'm not an expert but I do know a little about onions:
In the 19th century orientalism was a feature of art and design. All the artists referenced it (Hokasai woodblocks on VanGaugh paintings etc), William Morris floral designs, Liberty sold Japanese Woodblock prints, Macintosh furniture ...
I think it is European, possibly linked to the Arts and Crafts movement, certainly fits with Art Neuvo sensibilities. So much hunch would be late C19 to pre WW1. I would suspect English.
Very interesting piece. Off for another look!