Seems that I've inadvertently done this with my kale...the kale that I don't really know what to do with so I've just ignored it.
Whilst the caterpillars have been gorging themselves on the kale, the kale I don't care about, they don't seem to have noticed the rebirth of my mint (or they just can't see that far away). Normally the mint is CRAWLING with caterpillars that strip it bare within a few weeks but so far so good - the mint is going gangbusters. They also haven't noticed the SIX new tomato plants that have just moved onto the balcony, nor do they seem interested in new basil plants. Suckers.
Happy gardening...