The picture is of Sparaxis, and from what I have read so far, they will not survive a winter here. We get snow and some sub-zero temps.

If I plant them in late spring, will they flower the same year? How tall do they really get? Would I be better planting them in a container and bringing them in for the winter, and will they go dormant?

Sparaxis comes from the SW Cape which is a winter rainfall area. The plant is dormant over the dry summer period there. You will have to plant it in fall and it will not survive prolonged temperatures below freezing. You will have to plant it in a pot and then keep it in a warmer place during the winter (min +- 40 deg F, max +- 60 deg F). The leaves will appear before the flowers and it should flower in spring. The leaves will die in late spring to early summer when temperatures rise. If you are in a summer rainfall area then place the pot out of the rain and keep it dry. They do get about 13 - 15" and plant them about 4 - 5" apart.

Charles