I think a survival plant is one that you put in the garden once and it grows continuously with a minimum of care. A plant you can turn to in times of need
A survival plant should meet the following criteria (in order of importance):-
Survival plants on the other hand, take a little bit of work up front to get them settled in and then you can leave them to do their own thing. Some will die back in winter and resprout in spring, others will go all year round – the common thing with survival plants is that they are perennial and don’t require replanting every year. If allowed to, most survival plants will never need replanting. Many don’t need watering if you get a decent amount of rainfall, and fertilizer requirements are optional – just fertilize & mulch when you get around to it. The most work you’ll do is harvesting.