You can't grow cool-climate plants in hot climates

Summary

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 cool-climate and cool-season plants to eventually die here. That's a bummer for somebody who loves plants from places like cloud forests of Central America, the Páramo of Ecuador, Alpine plants from the Rockies or Southern Andes, etc. This phenomenon is also quite fascinating however, and goes far to explain why growing certain plant species or even entire clades (evolutionary groups) of plants is so impossible outdoors in certain climates. It all has to do with metabolism and something called compensation point.Like animals, plants respire. This means they burn sugars to create new tissue as well as the chemical compounds they use to defend themselves against fungi & insects, as well as simply to conduct daily metabolic processes required for survival.“Compensation Point” refers to the light intensity or CO₂ concentration at which the rate of photosynthesis exactly equals the rate of respiration in a plant. At this point, there is no net gain or loss of carbon—the CO₂ absorbed during photosynthesis is equal to the CO₂ released during respiration, and the oxygen produced matches the oxygen consumed.For a plant to grow (not just survive), it must operate above its compensation point. It must produce more than it consumes. That is, photosynthesis must exceed respiration enough to generate a net gain of carbon to -create new tissues- put some energy in storage reserves in the form of starch and sugar-produce defense chemicals (alkaloids, toxins, etc) and mechanical defense (spines, thorns, hairs, wax)- produce reproductive tissues like pollen, nectar, flowers and fruits/seedsBel...