The julie mango is an interesting mango in that it can either be a
Phenomenal mango with high precocity, high productivity, and multiple blooms leading to a long season
-- OR --
A finicky, unfruitful, disease-prone tree that is difficult to maintain and keep healthy
In talking with Gary Zill about my observations on the Julie, he indicated that the success or failure of growing the Julie depends largely on the soil in which it's grown. When grown in alkaline soil or when irrigated with calcium rich well water, the Julie can be a pain in the neck to grow. But when grown in neutral soil, the Julie is very productive and relatively care-free.
For the Julie-doubters (:-) who haven't seen a productive Julie in Florida, take a look at the below specimen (which is representative of dozens of similarly productive trees located in Tamarac). It has hundreds of thumbnail sized fruits in addition to flowers and dozens of 2-inch sized fruits.
Next up, here's an example of the other extreme of the Julie (in my neighborhood :-( ...) where high-ph soil makes it a pain in the neck to grow ph-sensitive plants like the carambola. The Julie tree has, at best, a dozen or so fruits. In contrast to the above Julie, most of the flowers fell off without setting fruit. A closeup reveals extreme interveinal chlorosis.