Polygonum bistorta or hydropiper?
Without the inflorescence I find the plant difficult to determine the correct ID.
The genus of both those species is now persicaria. As you say it is hard to tell without an inflorescence, a close up of the ochrea, the stem-clasping sheath at the base of each leaf would probably help. They are a distinctive feature of all Persicarias. To me your pictures look much more like Persicaria hydropiper than P. bistorta.
Thank you Ken, Sometimes, as you probably know, one comes across a plant in the wrong season, making an ID exceedingly difficult at times. Thanks again