Often key elements are found on the mantis underside, not visible in your picture. Your insect might be a nymph, not yet fully adult.

European mantis is the most common species.

She was very small, at least much smaller than I've ever seen. I think I read somewhere that the females have more ridges on their underside than males, and when I moved the tree for maintenance to powerwash my deck, I checked her out and I think it's female. I haven't seen her for a while now. She left shortly after that. Thanks for the reply!