May the blessing be said over a fruit tree growing in a movable pot [i.e. tree pot]?
Yes, a growing tree which is planted with earth inside of a pot may have the blessing said over it if it has produced blossoming fruit. Accordingly, in areas that fruit trees are scarce, or that people are unable to leave their homes, tree pots may be brought to their location for the sake of them saying the blessing. Seemingly, this applies even if the fruit tree is planted in a pot without a hole [i.e. Atzitz Sheiyno Nakuv].
 Yalkut Yosef Moadim 7 p. 613 based on Michaber Y.D. 294:26 regarding Arla; Nishmas Adam 152:1 regarding saying the blessing of Hadamah; Tosefes Haridbaz Yerushalmi 5 Maasros; Maharil Diskin 27