My Colmanara has really tall flower spikes. I bought it in flower I picked one of the tallest they had (I also checked the health of the plant though, didn't just go on the flowers).
Wow, that's tall, Rosie. I saw one at the garden centre that sort of size and it had a branched stem. My Colmanara "Masai Red" is in flower too, and has two stems, each unbranched and is about 18 inches tall.