First, dig around and see how much root system you find. You may have to plant fairly far out from the ficus to avoid a mass of roots that will compete with anything you may try planting. That may defeat the purpose, or may not. Ficus tend to have massive root systems that few plants can compete with.

Ficus hedge is at least 25 yrs old. Trunks are 9-12" in diameter and huge visible roots.
Is it viable to poss make a nick in lower trunk to encourage new growth.
I've asked the same question at several nurseries but they look at me s though I'm speaking a foreign language, and have no positive response whether there there is the slightest of possibility that this may work.
Thanks in anticipation of your response.

Nick in lower trunk will simply make a scar, not new growth.

Possibly making sure the bare areas are exposed to sunlight may promote new growth--but with mature trees as they are--unlikely. I'm not so familiar with Ficus as to predict if they can resprout from a bare trunk or not.

The thing to have done (too late now) was to keep the entire trunk exposed to sunlight via regular shearing to a narrow form so the original growth down at the base would have kept on growing. The plant--most plants--are likely to abandon growth that is heavily shaded since that growth is not going to be providing the same kind of energy to the plant as foliage in sunlight.

Examine this tall Ficus hedge--it has been carefully and regularly sheared since planting many years ago, and it has maintained green growth right down to the base:
{{gwi:504675}}

Another issue to consider is climate--any plant is going to sacrifice growth it can do without (heavily shaded, for example) in extreme weather (heat!) to preserve itself overall--and in your desert conditions, the base growth may have been sacrificed by the plant long ago in order to get established, or during particularly extreme weather. Also, the sheared hedge in the above example might have struggled in your desert climate, whereas in its far more mild location (near the coast) the extreme shearing was, for the plants, manageable.

I lived in the Coachella Valley for years, (La Quinta, specifically). Not sure what you wish to plant, but I would put raised planters on top of the roots of the ficus, and plant whatever I wanted in them.

The ficus has an extreme root system that could lift a house, crack a street or split a boulder!

The hedge is a beautiful thing. Of course you could plant bougainvillaeas in there, but those ficus mean business!!

I would just make a micro climate with pots or planters, put in a drip system, and enjoy whatever I plant.

Keep us posted! The only thing I ever grew in Coachella was garlic cloves (that were old and sprouting), and jalapeno. OH, and citrus!! I forgot all the wine grapes. We had many of those. Roses! My fav was Veteran's Honor!

Good luck!
Suzi

You could always plant other tough plants...like Pittosporum tobira. Plain form,variegated or "wheelers" a dwarf.
There's always Agaves... a nice contrast to the Ficus and in your climate wouldnt mind some shade.
Or,how about "Firesticks" ? blazing red that I think takes all heat you can make..but I'm not sure of that. A nice hedge of that with Ficus sounds pretty exotic.
Then,theres old faithful..boxwood. You would have to water heavily. It could work?
Tecoma stans? THAT I know takes full desert heat..

There is always too,,junipers. I'm not sure if they are good low desert plants..but the variety is huge. A silvery juniper is one nice look..and that helps the plant reflect excess light.