Could be a hydrangea. See if it blooms to confirm. The leaves should be double, opposite, serrated. It should have green stems from a crown that turn shades of brown, sand or gray as they mature.

I'm not sure what it is but I'll move this over to the Plant ID Forum where it will get more views and someone may recognize it.

Are the stems square or round?

It resembles a Salvia or another species in the Lamiaceae but that one image doesn't provide enough info to say for sure. Some more photos of stems, flowers, buds, etc., would be helpful. Some context would help, too. Was it purchased, found in a garden, possibly a weed, etc.?

Rub a leaf and see if it has a strong fragrance. I agree that it looks like a salvia or closely related.