I'm really not familiar with what works in your climate but I have a good deal of deep shade as well as dappled shade and I love to use begonias, lime coloured sweet potato vine (yes, it does just fine in deep shade for me and everyone is surprised because they never considered it before), impatiens, fan flower, coleus. All will spice up the space with colour and most will continue to bloom in our summers even through the worst of the heat as long as they are watered regularly. All are very forgiving of a bit of drought and come in may fabulous colours.
This time of year in Ontario we can get some good deals on the larger plants so I would suggest you just get the biggest ones you can find and enjoy looking at it full of flowers.
I was going to try to send a pic of mine but can't seem to figure out how to do it. I'm not savvy when it comes to digital cameras and sending or uploading photos.
Best of luck!