Horseweed
Do not feed. Horseweed has some diuretic properties and is also a potential skin irritant. It is said to take up significant amounts of cadmium when grown on soil contaminated with heavy metals and is not palatable to pigs, sheep or cows, so it is best kept away from your tortoise enclosure.
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I agree with EllyMae. Not edible. Further, you should go around and pull every bit of it out and throw it in the garbage before it goes to seed. Grab the stalk near the base and pull straight up to get the whole root out.