Using fusion to improve a fig tree is a valuable technique. However, it is necessary to use genetically identical material or the fusion my show differences in bark, leaf, etc. that can detract from the uniformity and believability of the design.

In this case seedlings of Ficus virens while very young were fused to create a sprout style tree. On careful examination of the trunks it is clear that they are not identical in bark character.

Ficus virens in a clump style created by fusion of seedling trees

Note that these three trunks do not look identical because genetically they are not the same