These grew great for me last summer, reaching four feet by October from seedlings. Grew them under grow lights in the basement from October til April and they grew slow, but steady. Planted them back out the last week of April, trimmed back the leaves so they wouldn't desiccate since I disturbed the roots. Of course, the leaves sunburned so I hacked them off at the very end of April.
Averages for the month of May have been 61.8 for highs and 45.2 for lows. The past week has been warm and we hit 90 yesterday, last nights low was 75 and we were up near 90 again today. Here is ALL the growth I got from end of April to now. I expected them to start flying with the heat, but that has not been the case -- these grew lightning fast for me all last summer.
As you can also see, I've been having to keep trimming the old petioles. Brown mush starts on the end and slowly works its way down, so I've been hacking that back every week or so to prevent it from spreading to the healthy tissue. I'm hoping they are just rooting in and one day will start flying? Dunno... I'm getting impatient.