There are certain fruits that grow on trees with unusual features, giving rise to the question of whether the Beracha over these fruits is "Ha’etz" – like for other fruits – or "Ha’adama." These fruits include papaya, banana, pineapple and passion fruit.
As for papaya, Hacham Ovadia Yosef ruled (in Hazon Ovadia – Berachot, p. 23) that since the papaya tree produces fruit within the first year after it is planted, it does not qualify as a Halachic "tree." This is based on the Tosefta’s ruling that a defining characteristic of trees, as defined by Halacha, is that they produce fruit in a slow, gradual process. As such, the Beracha over papaya is "Ha’adama." Nevertheless, given the different opinions that exist, the halachic status of papayas, as well as that of bananas, pineapples and passion fruit, remains uncertain. We recite "Ha’adama" over these fruits, since "Ha’adama" suffices after the fact even for fruits that optimally require "Ha’etz," but the possibility that these fruits require "Ha’etz" has certain important ramifications.
One example would be a fruit plate at a Kiddush on Shabbat that consists of grapes, melon and pineapple. Grapes certainly require "Ha’etz," melon certainly requires "Ha’adama," and the status of pineapple, as mentioned, is uncertain. If one wishes to partake of all three, he should first recite the Beracha of "Ha’etz" over the grape, followed by "Ha’adama" over the melon. The pineapple is then covered according to all views, since both Berachot have been recited. As the status of pineapple is uncertain, it is preferable to recite the Berachot over the other fruits in order to avoid a situation of Halachic doubt.
Another example is where one eats dates and pineapple. The individual in this case can either first recite "Ha’adama" over the pineapple, and then recite "Ha’etz" over the dates, or, if he prefers eating the date first, he can recite "Ha’etz" over the date with specific intention that this Beracha does not cover the pineapple. After eating, he should first recite "Boreh Nefashot" over the pineapple, followed by "Al Ha’etz" over the dates. If he would first recite "Al Ha’etz," this Beracha would cover the pineapple, and so he should recite "Boreh Nefashot" before "Al Ha’etz."
Summary: The halachic status of papayas, bananas, pineapple and passion fruit with respect to Berachot is uncertain, and so, in order to cover both possibilities, we recite "Ha’adama" over these fruits. If one eats one of these fruits – such as a pineapple – together with a fruit that requires "Ha’etz," one should either first recite "Ha’adama" over the pineapple, or first recite "Ha’etz" over the other fruit with specific intention that this Beracha should not cover the pineapple. If the other fruit is one which requires the recitation of "Al Ha’etz" after eating, one should first recite "Boreh Nefashot" over the pineapple and then "A Ha’etz" over the other fruit.