I bought a couple JRP in '07 or '08 which are in early stages of development, and have a couple seedlings in the ground. In no particular order, here are some observations:
1. They are BRITTLE.
2. They start growing earlier in the season than black pines, but grow a little slower. Needles open about the same time as or slightly after BP.
3. Candle-cutting is effective in improving ramification and density, but I'm still trying to get my arms around timing. One year, I did it at the same time as BP and it was a little late, this year I did it on June 13 (all at once, leaving long stubs on strong zones, short stubs on medium zones, and left the lower branch alone), and this process could have waited until July 1.
4. Bud-selection is probably more crucial than anything, JRP form MANY buds at branch tips...getting them down to 2 equally-sized buds per terminal in the fall creates order from chaos.
5. They are not as susceptible to needle cast as a BP here, but one has been invaded by scale on several occasions.
6. Shortening last year's candles (pruning between nodes to shorten branch length) hasn't resulted in advantageous buds along the remaining candle, nor at the tip of the cut. New buds appeared at the base of the cut branches instead. It appears that those cut branches will be sacrificed by the tree over time. This was in stark contrast to BP.
7. They take water much more slowly, but don't seem to suffer from overwatering. While the BPs next to it needed water daily in the heat of summer, this one needed water about every other day.
8. This one has been in this pot for 3 seasons and probably won't be repotted next year. I wish I would have used coarser soil, however, knowing that it would go this long between. Next time I'll use lava rock and akadama, 3:1.
9. The JRP in the ground are fine, but the 2 in pots seem to be suffering from a little iron deficiency this year. I was just noticing that the needles are a little pale.
Peter Warren will be back in a few weeks, and this will be one of the trees we'll tackle. I'll start a new thread on it, hopefully with some new photos and info.