Resemblance between central rosette's "towers" and small-plants' "containers".

[VViews]

In one version of the Ripley scroll (Bodleian MS Ash Roll 53), there is a structure which presents striking similarities to the central rosette. There are no jars in this one, but in many versions of the scroll, the figures atop the towers are holding flasks.
Interestingly this particular version was discussed in a 2016 talk by none other than Alexandra Marraccini.
Unfortunately, the date of this version is 1600.
Still, I think it is a relevant parallel, because the number of "towers" varies regularly  (4, 6, or 7) in different versions, so if this is the basis for the Voynich image, it could be based on an early version I don't know about.
Nice frog and nude figures too