Many thanks for all of the very useful information, especially to Eugene for (hopefully) solving a problem I had when trying to germinate G. cardinalis a few years ago. I treated it in the same was as you would other Glads and I don't need to tell you what happened ... or rather didn't happen! My local climate here is relatively cool compared to most of the US. It rarely gets hot (occasionally 32C but more often mid 20's with night lows of between 12 - 18C in summer. Usually, winter lows remain above -3C with no soil freezes and relatively few air frosts, although we have been seeing some changes over the past 4 years. It's a maritime climate - never very hot and never very cold.