Oh yeah, hedge needs to be cold hardy, so Areca palms are out. That cold spell five months ago taught us all a lot. We went down to 28, 29 degrees for a couple of hours on two consequtive nights.

I've seen some dense hibiscus hedges. I would go to my local hibiscus society and ask about the best garden variety for this application.

Walter's Viburnum is always green and has delicate white flowers .
Native to Florida and cold hardy .
Dense growth and first choice for Florida hedges .
Florida Privet is another choice of a Native for Zone 10 .
This link shows choices with photos .

Here is a link that might be useful: plants with photos

How about bottlebrush? They flower much of the year, attract hummingbirds, and can be pruned any way you want. (Tree-form or bushy.) Severe winter temps do take it back at the tips, but mine have survived and our temps here last winter were in the teens. The common variety is red, but there is also a white one, but it's hard to find.

I vote against the Oleander because it's poisonous and has flowers only on the ends of its sparsely leaved branches (at least that's the natural growth habit of the ones in my yard).
I second hibiscus. Some varieties do better close to the ocean than others. Here on the east coast, I have the best luck with red ones. All of my hibiscus came through the winter without any damage. They do sometimes get aphids when they're stressed. If the aphids are heavy, I just cut off the terminal leaves where they congregate. But mostly predatory insects take care of them.

Appreciate the feedback. But the hibiscus hereabouts were almost entirely devastated by the cold spell in early January. Will investigate the privet, virburnum and bottlebrush though, should be interesting. Thanks all.

silver buttonwood is a good choice. It flowers and has beautiful foliage. Although it eventually takes on a small tree form and you may have to plant some lower growers underneath it to fill in if that's gonna be a problem. Could also try a Pomegranate as well. Or Cape Honeysuckle. A mounding vine like Clerodendrum would eventually work too. I had one at my old house that was almost 12 ft tall and made a dense shrub.

A nice solution to screening that is often overlooked is the flowering vine. There are a million to choose from. The only thing you have to do is build a support or fence. It does not have to be elaborate either.

Do you want to cut/trim the hedges every week? Or is height and width no object?

I use viburnum around my swimming pool for privacy. Not exactly a flowering bush, except for short periods of time, but withstands cold and grow fast and thick. My suggestion.

Bouganvilla...you can keep trimmed as a headge. I have two different colors I alternated with. I planted back in the winter.
Becareful of hibuscus.. aphids.

Some Crotons work as a hedge...no flowers but very interesting foliage.

Also, Firebush can be kept trimmed.

Crinum..Queen Emma.. gets 5 ft tall... screams tropical. Grows fairly fast like to be fed.

Or try something not so conventional like
Breynia -snow bush. There's a hedge of it right down the street from me.
Grows fast-multicolored pink, green and white leaves.
Lakeview jasmine and pinwheel jasmine can be trimmed into hedges.
Someone here on GW has a bamboo hedge........cheryl

I forgot about Lakeview Jasmine, it's great. I had one of those in Tampa, when it bloomed, it was absolutely covered in blossoms and what a fragrance! But I can't find it anywhere now.

I tried to make a flowering privacy hedge with hibiscus. All the exotic hybrids like mary poppins, kiss & tell, sunset, irish eyes etc did very poorly -- were mostly covered with thrips and lost their leaves during cold snaps and generally looked ratty most of the time. On the other hand, my snow queen and fire & ice are doing beautifully x many years, kept most of their leaves even during the cold snaps plus they are beautiful to look at even without flowers, and no real problem with bugs.

One other thing you might want to investigate as a flowering hedge would be crape myrtles--you can get a variety that has shrub-like growth, they flower consistently throughout the year and can handle the cold snaps without any problem.

WRF

Crape myrtles do have an extremely long flowering season, but it is not quite throughout the year. They are deciduous and lose all of their flowers and leaves in the winter.

I have a crape myrtle that is a bush style one in Tallahassee that blooms at least 3 out of 4 seasons and doesn't lose it's leaves in the winter. Sorry I inherited it so I don't know the name but if you are interested in crape myrtles, make sure you don't get the wrong kind for your purpose.

Fascinating! I learn something new every day. I didn't know there were any evergreen crape myrtles. Thanks for the info.

Carol

what about thyrallis. Pretty yellow flowers.

I live in SW Florida and have many varieties of crape myrtle. I have never heard of nor ever seen an evergreen crape myrtle and highly doubt such exist.....I think they may have some other plant! Our zone is a 10b and my crape myrtle all lose their leaves and flower buds for several months. However, they are very hearty and grow rather quickly as mine grew about 3 feet in the first year. Also, I believe they all can be trimed either in a bush or tree, don't think there's any separation there either as I spent many hours speaking with folks at the extention and crape myrtle farms prior to purchasing the ones I have. I was told it is all in the pruning technique as to which you will achieve. There are numerous colors available and all are just gorgeous when in full bloom. They don't like too much water so the rainy season plays havoc with the flowers and also can turn the leaves various shades of green. I always use 10-10-10 fertilizer and let mother nature do the rest. Haven't had any issues with insects of any kind and we certainly have no shortage of ants here!!