Jayrad:

Most fruit trees and bushes need a minimum accumulation of chilling hours before they will fruit. After the chilling is satisfied, there is a certain number of degree days needed before bloom commences. So it is temperature controlled rather than daylenght.

Some blueberries will fruit with little or no chilling needed. My Southmoon is that way. I don't know what causes it to start flowering because it starts in October and flowers until April apparently with no chilling needed. Perhaps it is the shorter days of fall that trigger flowering in Southmoon. But this certainly is the exception rather than the rule if true. And even Southmoon blooms mostly in spring rather than fall or winter.

I'm not sure what the chilling requirements of Top Hat are. But it sounds like in FL, to do what you want to do, you would need an evergreen type that needs little or no chilling like Southmoon or Sharpblue. You can probably do what you want with blueberries but the right variety will be critical. They vary moreso than most fruit in chilling and growth habits. Find the right one and it will work for almost any situation. Get the wrong variety and you will be out of luck.

The Fruitnut

I can' answer any of those directtly, but the Tophats I bought from Home Depot that were already leafed out in he beginning of april have a nice crop of blueberries coming in already. I presume that they fruit rather quickly and right at the beginning of the season. Mine gets 7 or 8 hours of light a day and seems to be doing fine. It was, however, devstated by wind, and two of the three main trunks literally tore off from one of our common rain storms (its windy here). But the other bush at my mothers house is doing fine.

'Top Hat' has high chill requirements, which means it will need around 800-1000 hours of temps below 45F and above 32F in order to properly break dormancy in spring and flower. In order for it to do well in Florida, you may have to provide it with artificial chill after it drops its leaves in fall, which it should do in response to shorter day length. You could stick it in a refrigerator for 30+ days, and that should be enough if it is just a couple of degrees above freezing.

A better choice for Florida for a compact type would be finding a Darrow's blueberry (V. darrowi), not to be confused with the northern highbush 'Darrow'. V. darrowi is native to Florida and is compact with nice fruit. Your other choices would be some of the very low chill varieties like those mentioned by Fruitnut, but they will not be dwarf like 'Top Hat'.