I think its probably closer to mid-high 20s for a mature tree. Lychee, mango, and sapodilla are likely more cold tolerant. I was forecast for 28* for 6+ hours, and my 5' in-ground Ross Sapote has completely defoliated, but time will tell. I mounded mulch/compost around the trunk 2' high, and haven't removed it yet or done a scratch test. I took some 3g mamey, canistel, and green sapote inside that 28* night, but left them out for some nights between 32-35, and they've suffered leaf damage to varying degrees. My other container plants, which were out for the 32-35 nights, are barely showing any impact from cold (mangos, sapodilla, Luc's garcinia, lemon drop mangosteen, seashore mangosteen, allspice, rose apple, avocados, kwai muk).
The following is in the ground, and relatively unaffected at all by 28*: lychee, jabo, starfruit (still holding/maturing fruit), peanut butter fruit (AKA PBF, just finished fruiting 12/30), CoRG, pitanga, pitomba, acerola, pitangatuba, Savannah Cherry, white sapote, passion fruit, white guava, strawberry guava, tamarillo, mysore raspberry, jujube, curry leaf
Somewhat impacted:
20' Ice Cream Bean, yellow jabo, guarana, papaya (holding fruit), banana (holding fruit), 25' moringa (dropped 50% of growth)
Heavily Impacted:
Ross Sapote, 4' jackfruits (80% defoliation, buds burnt), 6' orange hog plum (100% defoliation, appears alive), solanum pachyandrum AKA Jolly Rancher Fruit (died back to main stem near ground, putting out small shoots)
