Vox Humana wrote:
...It looks like a very healthy form of smartweed (polygonoum)...
... It is an annual that forms spikes of very tiny
mauve/pink flowers.


That sounds like what we know as "lady's thumb" because of the
thumbprint on the leaves. However, our version has somewhat thinner
leaves than the picture. It doesn't get very tall, maybe 18". The small
flower clusters aren't much to look at. It pulls out easily, but there's
always more growing.