I know mine develop differing levels. One MB has a beautiful deep blood red from the petiole and deep into the vein of the leaf, and another MB has a more normal reddish colour that isn't as striking.
Growing a cutting for years is not an identifier that would be recommended.
There are going to be variances in all the different specimens of the MBs and PJs etc etc. to say with confidence that PJ get the red petioles is not really scientific. The vast majority of MBs and PJs I’ve seen exhibit the differences shown from the red petioles.
How do you know for certain your PJ with red petioles is in fact a PJ?
I’d consider it more of a guideline that I’ve used and seems pretty good so far
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