Answer: According to the Monrovia on line plant descriptions, this plant might not really be all that well suited to the warm climate of Alabama. It is listed as growing well in USDA winter hardiness zones 5 to 7 which includes only the northern half of the state (the southern half is zone 8); then it is listed as growing well in the American Horticulture Society's summer heat zones 1 to 7 -- which would basically include only a very narrow band at the northern edge and a tiny northeastern corner of the state with the remainder of the state being warmer. Overall it is better suited to cool summer areas and areas that provide a mild winter yet still allow for an adequate chilling period. You might check with your local county extension and local professionally trained and certified nurserymen and see if they think this plant could grow for well for you; if not, that may explain why you are unable to locate it in your area.
Here is some additional information about this tree that you may find interesting. You may need to cut and paste the complete url to make it work correctly.
here you will need to scroll down to click on the name
Q&A Library Searching Tips