Pokeweed is a plant native to the United States. Although poisonous to most mammals, the berries are perfectly fine for birds. The young shoots, when prepared properly, can be safely eaten by humans in small amounts according to unofficial sources. The berries should not be eaten by humans, as even just a handful could be dangerous to an adult, but historically some people have used a berry or two here and there for medicinal purposes. (That link is about pokeweed poisoning, might be good to bookmark it.) The berries have also been used as food coloring, so it seems a small amount used as dye is not especially dangerous.
Because of its strange coloring and appearance, it's sometimes associated with the planet Uranus. If you're like me and prefer the seven classical planets, it can also be associated with Mars. The berries produce juice of a vibrant magenta-like color which can be turned into a magical ink. It's possible that the United States Declaration of Independence was first written in this ink before being updated with iron-gall ink after the original writing faded from sunlight exposure.
Learning about a plant and how it's been used historically can help us decide how to use the plant in spells. From these details alone, we can take a few guesses as to what this plant can be used for magically:
It's poisonous to humans, so it could be good for baneful workings.
It's eaten by birds, so it could be good as an offering if you follow a deity associated with birds.
It's associated with Uranus, meaning it could be good for that god/planet.
It's native to the US, so it might be a good offering for land spirits in that area.
It might be used for freedom because of its use in the Declaration of Independence.
All of these potential uses make it a great candidate for making magical ink, so I gathered some up and will be doing that in another post soon!
Stay safe!
-me