Cliff was recently mentioning to me that he had several varieties not fruiting much at all and he thinks its due to his relative lack of heat. I also have a significant problem with getting some varieties to fruit. Cliff mentioned Chico, GA-866, Li, and Sherwood not fruiting in 15 years. I have all four of these and none of them have fruited any significant amount for me in 10 years.
In fact, no jujube variety fruits super well in my yard. The only one which regularly produced a full load every year was Tsao, but they taste like cardboard so I took it out. Honey Jar and Sugar Cane produce well some years and not others. One thing that makes things even worse for me is I have too little sun and too close a spacing, but Tsao at least didn’t seem to mind that.
According to Ashton’s jujube book, the plants need 72-80F dry weather at bloom time to set well. But, he doesn’t say much about fruit setting for different varieties. I am now thinking the major thing to look for in variety selection for us folks outside the west is fruit set.
It would be good to hear others experiences with fruit set. I have heard Li setting well some places, but there are many Li variants so its hard to put much meaning into that.