I bought this plant at a grocery store a few years back with the wonderfully informative tag of 'garden herb' in it. It was the sole survivor in a flat of plants that looked like they had never been watered. I took pity on the poor thing and stuck it in my garden. It is perennial in zone 3. I have tried to identify it myself, but to no avail. Would love an identification! :)
When crushed, stem and or leaves will smell like celery and can be put in salads or stews. WATCH it tho - or it will take over your garden. As I remember it is a root runner as well as lots of seeds and goes everwhere!!! Sunset makes it sound rather benign, but if the slightest bit happy and not watched it will take over. barb