Hello,
foliage.CullDistanceScale is a useful CVAR to quickly adjust the culling distance of any foliage in the scene, however it does not work as expected when compared to the other DistanceScale commands like grass.CullDistanceScale and r.ViewDistanceScale.
The latter CVARs allow you to go above 1 and effectively multiply the view distance, but this is not the case with foliage.CullDistanceScale. It only goes from 0 (infinite view distance) to 1 (default).
It would be nice if this is kept consistent, otherwise solutions like massively increasing the FoliageTypes end cull distance and lowering the default foliage.CullDistanceScale value to 0.25 or 0.5 to have room to easily extend the view distance is necessary.