I love red hot poker plant but have never been able to grow it in central MA - it seems only marginally hardy in zone 5. I did see one on a garden tour this weekend, though, and it exhibited the same conditions that you describe.....

Hmmmm....I've been growing poker plant. So, the bottom half turned brown and fell off before it flowered? I've noticed that it blooms kind of like foxglove where the bottom dies out first and works its way up the stalk.