I have 2 vexators, one from Puerto Rico, the other from Excalibur. Both are over 8 years old. The one from Excalibur flowered for the first 1.5 - 2 years, setting really sparse crops before giving me a bumper crop this year. The one from PR, has flowered for 2 years, but still sets a sparse crop. Also, the one from PR has sour fruits, while the one from Ex is sweeter than sabara. Perhaps there is some variation in Vexes?