I have two ornamental ficus trees which I've had for approx. 2 years. They are in a sheltered and fairly sunny aspect (prob 5-6 hours of sun during summer months). Both trees have been steadily losing leaves. It only from the inside branches. Thus gives them a sparse 'Hollow' look. There are literally no leaves other than on the very ends of the branches. I have tried fertilising and they are showing new leaf growth, but only on the ends. The trees literally look dead when you look beyond the outer layer of leaves. I really don't want to lose them. Thanks in anticipation. Nikki P.s they are shaded by gum trees for some of the day.
Outdoor Ficus Trees
Certified GKH Gardening Expert
I am seeing two likely possibilities. The first is that the inner branches may not be getting enough light to sustain them.
The second, is that it could be rootbound and not able to take up enough water.
If you don't want to re-pot it just yet you can poke something long and skinny down into the roots to give them access to water in the center. I would also recommend that you apply dolomitic lime to the top to keep the pH stable, and give back a little magnesium and calcium to the tree.
To get light to the center, you can either use soft string to keep the branches apart to let light in, or do some LIGHT pruning to the tree to allow light to get in the center.
Here is are two links for more information on this tree's care: https://www.gardeningknowhow.com/houseplants/ficus/ficus-losing-leaves.htm