can itrim down mimulas and will they grow back

Is it like the one that I've just posted a picture of?
If so,just snip them off above a new shoot & they will come back & flower.
I do this routinely,a couple of shoots at a time so that they are always in flower.

Yes, if they are the spotty types derived from Mimulus guttatus and M luteus you certainly can cut them back and they often re grow very well even flowering again. Where is your picture?

Fractal,click my avatar & the picture is in my photos.Mine is the perennial Mimulus (Cardinalis).