Blueberries are the fruit people most often tell us they have failed with, and almost always for the same reason. They are not difficult plants. They are plants with one requirement that is absolute, and Central Florida sand does not meet it on its own.
Acidity is not a preference, it is the whole thing
Blueberries need soil between pH 4.5 and 5.5. Not six, not neutral. Below about 5.5 their roots can take up iron; above it they cannot, however much iron is present. A blueberry in the wrong soil yellows between the leaf veins, stops growing and dies slowly over two or three seasons, and no amount of watering, feeding or sympathy changes that.
So test before you plant, with a cheap probe or a county extension test. If you are above 5.5, the honest options are a raised bed or a large container filled with an acidic mix, rather than trying to acidify open ground, which works for a season and then reverts.
Three habits keep it right once it is right. Mulch with pine bark, two to four inches, renewed yearly, which acidifies gently as it breaks down. Never use lime, and be careful with mushroom compost and most municipal composts, which are often limed. And check your irrigation water, because well water in parts of Lake County is alkaline enough to undo the soil underneath a plant over a few years.
Plant high, and plant two
Set the root ball slightly proud of the surrounding soil rather than level with it. Blueberries are shallow-rooted and resent sitting wet, and a plant set low in sand collects exactly the water it does not want.
Plant more than one variety if you possibly can. Southern highbush blueberries are self-fertile, so a single bush will fruit and the sign on your plant is right about that. But cross-pollination between two varieties gives bigger berries, more of them, and an earlier harvest, and the difference is large enough that we would rather sell somebody two plants than have them disappointed by one. Emerald and Jewel are the pairing we recommend, because they flower together and ripen in sequence, which stretches the picking season.
Southern highbush, not what the catalogues sell up north
A northern highbush blueberry needs eight hundred or more chill hours and will never fruit properly here. Southern highbush varieties are bred for low chill: Emerald wants about 250 hours and Jewel about 200, which Central Florida reliably provides. This is the single most common reason a blueberry bought online from out of state never crops.
Water, feed, and leave it mostly alone
Water daily for the first week, then two or three times a week through the first month, keeping the soil evenly moist rather than alternately soaked and dry. After the first season, deep watering once or twice a week in dry weather is enough, and a mulched plant needs less than you think.
Feed with an acid-loving fertiliser, the sort sold for azaleas and camellias, lightly in spring once the plant has settled and again after harvest. Lightly is the operative word. Blueberries have fine shallow roots that burn easily, and more fertiliser is the second most common way people lose one.
What to expect, honestly
A plant from a one or three gallon pot will put on growth rather than fruit in its first year, and pinching off that first season's flowers makes for a far better plant in year two. Expect a small crop in the second year and the first genuinely worthwhile harvest in the third. Mature southern highbush bushes here reach five to six feet and keep producing for well over a decade.
Prune lightly after harvest rather than in winter, taking out the oldest canes at the base to keep young wood coming. A blueberry fruits best on wood that is two or three years old, so a bush that is never pruned slowly fills with unproductive stems and crops less every year.