Here is another picture showing that it spreads. Not fast, or it would be out of here a long time ago. You can barely see a small plant growing in the background in the upper right. I have pulled several a few months ago and all were attached by roots to the main plant.
It is growing in a dry, shady area, with no supplemental water.
Mike

almost looks like phytolacca, has it bloomed?

It's in an out of the way part of the garden. If it has bloomed, I missed it.
Mike