Janice, This is also known as "limbing up", when it is done to existing multi-stemmed shrubs such as Oleanders, when it is desired to make them appear as multi-stemmed trees rather than shrubs with branches to the ground. What you decide to use in this area will depend greatly on whether it is full sun or shaded. Hibiscus really only works with enough sun, Podocarpus will work with either, but do eventually want to get to be big trees, so will require regular shearing to control size, and the trunks may eventually look out of scale for the size of canopy head you wish to maintain. I would consider using shrubs that will remain at more or less the size you prefer. Other flowering shrubs that come to mind, would include Feijoa sellowiana/Pineapple Guava, Tibouchina urvilleana/Princess Flower, Psidium cattleanum/Strawberry Guava, or Bambusa multiplex 'Alphonse Karr'. Sasanqua or Japonica Camellias could also serve your purpose. None of these will stay narrow indefinitely, and will all need occasional pruning to control width on both sides of the fence, although the bamboo is more vertical, so it would require the least.

I've always loved Tibouchina. We had a beautiful Princess Flower growing outside our bay window when we lived in California. I planted several Tibouchina Urvilleana when we moved to Florida, but they were in too much shade and never did well. I recently bought a Tibouchina Heteromalla at the USF Fall Plant Fair for our new house. It's proving to be a more finicky variety of Tibouchina and did not do well in January's freeze. This thread inspired me to do some research on the naming conventions used for Tibouchina and I'm finding that there is an unusual lack of agreement on the Web and in the gardening books . It doesn't help that there are "Glory Flowers", "Glory Trees", and "Glory Bushes" all within the genus Tibouchina. But the common names are not consistently applied. For example, there are a multitude of sites on the Web that refer to tibouchina urvilleana as Princess Flower and Glory Flower. My guess is this leads to a lot of unnecessary confusion for consumers. Which is a shame, since Tibouchinas are "glorious" plants. The link below may be helpful. It summarizes the major varieties of Tibouchina. Here is a link that might be useful: Tibouchina

I'm becoming a broken record on this one because I love this tree so much, but I gotta mention dwarf ponciana (aka pride of barbados) as a lovely little tree. Longer bloom season than the Royal ponciana, fast growing but doesn't get big. I bought mine four years ago at a charity plant sale for $3. It was a foot high. It's 15 feet now, and spreading nicely - actually throwing some shade. It did take some work the first year to control the shoots coming up, but once it realized I was serious about it being a tree, it acquiesced. I'm still trying to convince the golden dewdrop and a hibiscus that I am similarly serious. And the great advantage of a tree that is doing what I want without much work from me? Well, there's not much work for me. But I was also able to leave the dwarf ponciana alone enough this year that my cardinal pair found it worthy of a nest. I also see lots of different butterflies and even the occasional hummer. Lemme know if you want seeds. It will be awhile before they're trees.

Here's some info that I posted a couple months ago in response to another quetion about false rosemary. I love my false rosemary and it is one of the toughest plants I've ever grown. It thrives in both drought and rainy conditions as long as it has well drained soil, blooms beautifully, has wonderfully fragrant foliage, and really attracts bees. Once it was fully mature it also became thick enough to smoother any potential weeds and since it's evergreen I never have to weed under it. I really need to trim mine back but I love how it looks so much that I haven't been able to do so yet. To propagate it just pin some of the longer braches to the ground and partially cover them with dirt. The branches will root themselves fairly quickly. My main plant is surrounded with smaller plants where it's branches have layed on the ground and rooted themselves. I bought my original plant at a native plant sale up in Gainsville several years ago and it was in a 3" pot. This is a florida native that is also known as a scrub mint in the Conradina genus. This particular variety gets between 2 and 3 feet tall and as wide as you will let it. I've had this plant for about three years now and have never had any problems with it as long as you don't count the fact that when it is in bloom it is constantly covered in bees. Even though I walk past this plant and brush against it while it's in bloom none of the bees have paid me a bit of attention. I believe that there are 4 different varieties of Conradina native to florida, two of which are endemic and endangered and a third is endemic and threatened. My plant is probably the fourth variety, Conradina canescens, but I'm not positive. As the first picture shows the plant is slowly trying to swallow up both my plumbago and my bleeding hear vine. The trash can in the background gives you an idea of the plants size. This is a plant that loves full sun but will tolerate some light shade (mines under a moderately large multi-trunked crape myrtle) and needs plenty of room to grow! Yes, my swamp sunflowers are Helianthus angustifolia. They do spread but so far I haven't had an issue with them, when they started migrating beyond the area I wanted them in I just just off the babies with a shovel and pulled them out. The native monarda is Monarda punctata and does have the lavender and white flower bracts. One native plant I forgot to mention that makes a great background plant is the Sparkleberry (Vaccinium arboreum). It's north america's largest member of the blueberry family although the fruit doesn't taste all that good. Here is a link that might be useful: Sparkleberry