Originally Posted by pjkfarm

Or maybe the chemistry is different - the majority of our nursery material is hardier when young - we think that this is because these plants when they evolved figures out that early in the year it wold be colder, so changed their chemistry to account for this - as they grow older, less risk of cold, so thy no longer need that "antifreeze". This goes for both annuals as well as perennials - shrubs, trees, etc. Of course bananas today are tropical, but like Sikemmensis or basjoo, some of them had cold beginnings (or maybe all of them, with just some evolving into true tropicals, but not loosing that early genetic trait?