Height, width, backdrop? Understand that if you have a solid fence behind the hedge, depending upon how the sun will travel in relation to the hedge run(s), there can be some combinations where the shrubs will probably not get sufficient sunlight at the areas near the ground to sustain low growth. Since you mentioned planting around the hedge, and in front of it, those plants can also shade the lower portions of the hedge, further discouraging low foliage. I recommend taking into consideration the maintenance of the hedge when planning neighboring plantings. Many bougainvillea plants have thorns; while beautiful to look at, they can be less pleasant to prune, or bump into, while pruning a nearby plant.

I recently planted a hedge of "Eugenia/Cherry Brush/Monterrey Bay". Some have grown over 7 feet in less than a year. I plan to build a full hedge around my front fence. So far, I have had good success with these.

There are far too many hedges in the Southern California area, I think. They just get planted because they are low maintenance. Everything else will eventually wither in the yard if it is not cared for but those bushes and hedges keep on growing. I have seen some yards where, over the years and over the course of several different owners, pretty things growing in the yard gradually become replaced with ugly bushes and hedges.

If I can make a suggestion, why don't you take a look at the Edible Landscaping section of this this forum? There are many bushes/hedges there that produce little ornamental flowers and are quite attractive.

Hibiscus can make a nice hedge, but keep in mind it be vulnerable to white fly infestation in Southern California. If it gets 100% full sun exposure at all times of the day it is also going to need consistent watering. I'm rather fond of Australian yellow snake vine (Hibbertia scandens), it's growth habit is somewhere in-between a bush and a vine. Attractive foliage and a few cheerful yellow flowers, especially in June.

Some varieties of Camellia can make a good hedge.

I'm trying to get rid of Eugenias I planted on either side of my garage. They grow up into the eaves if they are not regularly pruned - like every week. They are very tenacious, not succumbing to Roundup, stump remover, an ax to the cambium, or even smothering with a plastic bag. At least they are not growing up into the eaves any more, but there are still green branches poking out from under the plastic bags, so they may give it a try. They also get psyllids, but they don't kill the plant either.

Pittosporum silver sheen is popular for a hedge, but it gets phytophthora (root rot) easily, so they have been dying off here and there in Orange County.

Toyon is a drought tolerant plant and birds love the berries.

Rhododendrons and azaleas are slow and not a usual choice for LA conditions.

Rhodies and azaleas like water and acidic soil. They languish in southern California. If you want something reminiscent of the east coast, Camellias, on the other hand, might work, provided that you can give them a little sun protection.

I currently have a little Toyon hedge and I used to have a long hedge of Grewia in Orange county which was bulletproof. I also like bottlebrush hedges, although they are slow growers. The hummingbirds that they attract are so amusing.

Not sure about your location, you may have too much sun, for a favorite hedge here, very dense right down to the ground. The Escallonia, available in many varieties and sizes. It grows well here in the Napa Valley as well as my old location on the Monterrey bay, even along the beach where the wind was no problem. Al