Why you can’t grow cool-climate plants in hot climates

Since moving to Deep South Texas 4 years ago I've come to realize that many plants I used to love growing in the cool mild maritime climate of the SF bay area are impossible to grow where I live. This is not just because of the high daytime heat. It's not as simple as that. Specifically, it is the high heat during the night (and those warm nights are a direct result of the humidity) that causes…