They do not do well here. Trying to keep them is a pipe dream.
What's the meaning of the phrase 'Pipe dream'?
A 'pipe dream' is an unrealistic hope or fantasy.
What's the origin of the phrase 'Pipe dream'?
The phrase 'pipe dream' is an allusion to the dreams experienced by smokers of opium pipes.
Opiates were widely used by the English literati in the 18th and 19th centuries. Samuel Taylor Coleridge was one of the best known users, and it would be difficult to claim that the imagery in surreal works like
Kubla Khanowed nothing to opium. Lewis Carroll, although not known to be an opium user himself, makes clear allusions to drug use in
Alice's Adventures in Wonderland. Sir Arthur Conan Doyle has his hero Sherlock Holmes visit an opium den - although that was for research rather than consumption.