I typed weed with red stem and a cluster of dark blue berries into Google and the first hit back was for COMMON POKEWEED: Phytolacca americana. The pictures were a near perfect match for what I had snapped above. This one turned out to be super easy to identify.
Now that I had it named, I was curious to see if I could eat it? Those berries looked awfully tasty.
From the above link:
Toxicity: All parts of common pokeweed are toxic to humans, pets and livestock. Roots are the most poisonous, leaves and stems are intermediate in toxicity (toxicity increases with maturity), and berries are the least toxic. Since common pokeweed is not very palatable, most animals avoid eating it unless little else is available, or if it is in contaminated hay. Horses, sheep and cattle have been poisoned by eating fresh leaves or green fodder, and pigs have been poisoned by eating the roots. Children are most frequently poisoned by eating raw berries. ...
And it goes on from there. The description even suggests that the plant promotes mutation and possibly cancer. Yikes. Glad I didn't grab those berries and take a bite.
Even though it's poisonous, pokeweed isn't without some interesting uses. First off, if you're exceedingly careful, you can eat it. But for practical uses, skip the eating and use it for something more novel: to make ink. Now there's a fun little project to try.
Learn more about Pokeweed here.