We have been searching these out for decades now. There are
many perennial vegetables in the tropics, but few in temperate
climates. In the past they filled the "hungry gap" in April, when the
last year's crops had been eaten over the winter, and the newlyplanted
crops were barely up.
We have listed zones for these since they overwinter. Please
look under the individual vegetables for more on how to grow
them. See also our permaculture books.