Longwood Gardens in the late fall uses sages that bloom fall to spring: salvia leucantha, salvia maderiensis, and the common pineapple sage, and last year rose-leafed sage. Flowering maple "abutilon" should work. What about angels trumpets. If you grow them in a really large pot, really large, they would probably bloom all year. There are also lantanas that should bloom all year, as will cuphea. The list is truly endless. Check out these online sites: Singing Springs Nursery and Plant Delights, they both have good descriptions and photos. I wish I had such a conservatory. My florida room overwinters many of the plants mentioned above. They don't always bloom abundantly for me, but that is because there's a roof, most of the plants are new cuttings, and they only get direct sun in the afternoon. Have fun.