This summer here an Atreano fig bush in ground has well over 100 feet of trunk and limb but only one fig fruit – probably because it gets only about 4 hours of direct sun and was totally topkilled by winter. However, the limited light and total topkill does not prevent similarly situated Mt Etna fig bushes from setting fruit and ripening much of it.
A differing inherent production capacity of fig varieties is made clear in this example with the Atreano fig bush, in photo. The Atreano has engulfed a Mt Etna fig bush that has three trunks barely pushing out through the Atreano and yet the three Mt Etna trunks have set a dozen figs, despite the limited sun and the additional partial shading from the Atreano.
The biggest Etna trunk set only a single fig because it is almost entirely swallowed by the Atreano and gets virtually no sun. The two smaller Etna limbs closer to the edge of the Atreano get more sun and set more fruit, while none of the many more Atreano limbs set fruit, except for one fig.
It might be thought that the engulfed Etna has its roots constrained which is causing it to fruit, whereas the Atreano is free to expand roots and therefore grows limbs rather than set fruit, however this is not the case with similar Etna bushes beside and behind it. Those Etna bushes are growing unconstrained by any other bush and are all full of fruit.
Varietal difference has enormous impact on productivity in marginal growing conditions that are sun-limited and affected by winter top kill, which was total to the mulch or ground line. Atreano is known to be an extremely productive variety, though evidently not under conditions of limited sun and/or winter topkill, as experienced here over several years.
Photos below: Productive Mt Etna limbs – inside blue rectangles – engulfed by non-productive Atreano limbs:
Fully productive Mt Etna bushes (pictured) adjacent to unproductive Atreano bush (not pictured):
The Atreano with many more feet of trunk and limb set virtually no figs, while the little engulfed Etna planted beside it only to be swallowed up is producing despite all odds. Could not be a greater demonstration of inherent capability of variety.
Photos below: Flowers and Brooklyn White fig tree fruiting after total winter topkill:
Photos below: Takoma Violet (Mt Etna) fig bush. This Etna bush at the dry top of a bank partially survived winter topkill. While some trunks died to the ground, others survived to 4, 3, and 2 feet tall. Temperatures bottomed-out at about 3 F, about 10 degrees warmer than the previous two winters when no fig limbs above mulch cover or above ground survived. This Takoma Violet Mt Etna bush carries well over 50 figs that should ripen before frost and reaches about 8 feet tall. Mt Etna bushes lower on the well-draining steep bank similarly semi-survived winter and are laden with fruit, while the Etna bushes at the very bottom in the spongy wet all died to the ground but have grown back to bear a limited amount of fruit. (Excess water makes plants/trees in general more susceptible to freeze damage, thus the longstanding recommendation to not plant fig trees in soggy areas in cold climates.)