Thanks, ehBeth.
This year, I'm keeping it very simple -- white geraniums and pots of wild grasses. It's not a big space, and the winds and intense afternoon sunlight make it a hostile growing environment. So ... baby steps. Watering is problematic: Too much rots the roots because there is no real drainage, too little and the plants become stressed in a very short time. It's a much bigger challenge than my former terrestial garden, but much cheaper.
Another problem is my cats. I reserved a corner for them with a large, low circular planter of cat grass with a terra cotta pot inserted to hold water. Over that is arching a wonderfully twisted tree branch (found in the ravine) for them to climb over, pretend to be mountain lions, and scratch. The problem ... it seems the wild grasses among the geraniums are more fun and tasty than the cat grass.
Last year's plants were sad and spent by August, partly because of the environment and partly because I had purchased Loblaws' Gigantico varieties. I've learned since that these Gigantico plants are grown in California where they can be started far earlier than our own (hence their size) but because of that their lifespan and hardiness is less than local stuff.
I really must get over to Edwards Gardens and the Toronto Botanical Society -- it's so close and apparently has scads of resource material.