warm temperate and subtropical plants in various climates
I'm breaking this off from the other thread, because one thread can only hold so much inanity.
I can't believe I'm going to have to waste time on this logic exercise, but here goes.We need to classify plants by absolute ranges of hardiness.Let's just say 0F, 20F and 32F to keep things simple.Of the set of all plants hardy in each group, some of them will come from cool summer climates and some of them will come from warm summer climates.So this has nothing to do with "I don't know, diversity tends to go up as the climate gets hotter." Of course, generally speaking, there are more species in the tropics versus the tundra. That's not horticulturally relevant when I said I was only talking about "temperate and subtropical plants."
Of any set of plants above, more of the warm summer ones can grow slowly in a cool summer area than the cool summer ones can tolerate a far warmer climate. This is a simple fact that would be recognized by any enzymologist. All enzymes denature at some high temperature set point; obviously they all stop functioning in a conventional sense at 32F, but they don't denature.
There are literally a handful of temperate and subtropical (again, assuming the basic winter hardiness requirement is met) that will not grow in Cornwall England because it's too chilly for the plant to survive. (never mind blooming) There are hundreds of varieties of plants - thousands if you count rhododendron hybrids - that will DIE in the US SE because summers are too hot. When something like a Hedychium isn't grown in the UK, it's because it's too chilly for it to bloom, not because it will die in an absolute sense. People have nursed crape myrtles along in the UK.Again, they just don't bloom or grow well. They don't die.But there are no Cautleyas (ginger relative) in Orlando because they come from high elevations and will die in Florida.
Thus my statement:
As I've said before, far fewer temperate or subtropical plants need a warm summer as need a cool summer.
Is perfectly logical from the simple standpoint of survival. Which, after all, is square one in growing a plant. A cool summer isn't going to magically bring back the Eucryphia I tried to grow from the dead. (or the several Monkey Puzzles I've tried - there, the thread is about conifers!!! LOL) A freakishly hot summer in the UK COULD make a crape myrtle bloom there.
I could spend the rest of the evening citing examples. Please, don't make me. Many Brugsmansias will grow in the Bay Area, slowly perhaps but they will bloom.'Charles Grimaldi' will grow in central Florida or the Bay Area, but B. sanguinea dies in Florida.Again, the plant enzymes can tolerate a cooler summer than in their native ranges, but cool summer plants cannot survive going over their temperature limit. Even a 50% Cornus nuttallii ('Eddies') dies miserably in the east - believe me I know from experience. Yet there's a picture of a forlorn Cornus florida soldiering on in Norway. Not happy, but not dead.Rhododendron hyperythrum, the Taiwanese savior of Southeastern rhododendron enthusiasts, will grow in Scotland.Conversely, hundreds of high elevation Chinese rhododendron species have no hope south of the Mason-Dixon on the East Coast. (or recently, south of coastal Maine!)
This post was edited by davidrt28 on Wed, Nov 28, 12 at 22:46