If it is Yaaro then several sites say that it is edible. It is in my tortoise pen but I don't know if she is eating it. I couldn't decide whether to pull it out or not.
It sure looks like yarrow to me, with a flower stalk pushing up on the top left of the photo. Can you show us a picture of the entire plant?
One reads both that yarrow is safe and not safe, depending on the source. I go with "safe!" My Russian tortoise loves browsing it and regularly turns down other foods just now. Last year she only took the occasional bite; this year when she came out of hibernation, it was a big YES for her.