I am looking to add more perennial plants to my shade garden on the north side of the garage. I would say it is mostly full shade, and the edges get part shade. I want more flowering plants in shades of red/pink/white/purple. I am looking for something that gets between 24-30 inches high or so to go in the back.

I was looking at astilbe, but it seems they prefer light shade if anything, not full shade. I spotted astrantia. Some places say it does well as a part to full shade plant, and others say it does well in full sun to part shade. So tell me, what does it actually prefer? I want to put it in my shade garden, but now am questioning to whether it would actually do well in the full shade on the north side of the house.

Right now in my garden there I have "patriot" hostas, japanese painted ferns, lamiums, ajugas, & lily of the valleys. I am looking to put in heucheras, dwarf bleeding hearts, and possible pulmonaria, as well as a taller shade plant & hopefully a flowering one too like astrantia or astilbe.