Scrophularia species. It would be useful to have a picture of the foliage and a scale.

When you say it is growing in your greenhouse do you mean you planted it or it grew by itself? If the latter it could be the native Scrophularia nodosa. Figwort.

Thank you! it's def figwort! your a star, we didn't plant it, it just appeared there is no other plants around either it has grown to nearly 5 foots