A little late is better than never. Ideally, needle pulling is a late fall to winter activity. On JBP that grow slower (corkers), or are weak (recently repotted, underpotted, constantly candle-cut for ramification and small needles), it is ok to wait longer to pull needles.
The reason why is that green needles contribute to photosynthesis and therefore, the longer they remain on the tree, the stronger that tree can get.
So here are a few examples of early May needle-pulling.
First up is this corkbark JBP, ‘Taihei’, which is a slow-growing tree that I do not decandle. I repotted it last year, and wired it, so I waited until now to pull needles. I will prune, wire and pull more needles this fall.
Next is also a corkbark JBP, ‘Hachi Gen’ on its own roots. It is under potted, and needed to be repotted last year, but i didn’t get to it until this year. I also don’t decandle this one,
After. Much more even, definitely needs to be detail wired in the fall.
Finally, this JBP has been kept in “show-shape” for four years now, and finally was shown in the USNBE last fall. I repotted it this spring, and just pulled a few old needles to tidy up the undersides of the pads. Our annual Alabama Bonsai Society show resumes next weekend and I thought the tree still looked good enough to show.