I live in a relative cooler climate in Central Coast of CA. low 40's to low 80s, with a few extremes. See
https://feijoarecipes.wordpress.com/2017/11/19/frank-serpa-fremonts-feijoa-king/ about an early Feijoa pioneer in CA. I have 4 of Frank Serpa's cultivars along with some other selections (from others) and New Zealand's Triumph and Mammoth ones. The Edenvale Late, Improved Cooledge, and other Edenvale are surpassed by the New Zealand varieties in both size, production, and taste. Unfortunately, over the years, the Edenvale varieties have had to survive shade and competition from some huge avocado trees. Mammoth and Triumph are well established (6ftX6ft) and taken care of with no competition. The Edenvale group are being eaten by avocado roots and debris so it is an unfair competition. I was introduced to CRFG many years ago by a friend, John Moore, who really knew his Feijoas, connected me with Serpa, and even selected one (Moore) for outstanding characteristics. He told me there was a red one he encountered. I would suggest there are some excellent Feijoas out there like New Zealand selections and worth finding them.