Currently; about 1 1/2 inches.
That’s what I thought. Seedlings generally have longer needles than the varieties used for grafting.
This tree has 1 inch needles:
It’s the variety most often grafted on JBP rootstock. The trunk is Lodgepole.
This is a Zuisho, grown from an airlayer:
It’s needles are about 5/8 inch. This tree was airlayered by Julian Adams. Julian bought his original Zuisho from Bill Valavanis back in the 1970’s. Julian tells me it was the last one Bill had for sale, and it was cheap because it wasn’t very healthy, and Bill thought it was going to die. Julian saved it. And that tree has been cloned via airlayering and cuttings.
Next we have this Kokonoe:
It’s needles are about 3/4 inch. This tree was once grafted onto JBP rootstock. When repotting it, there were two sets of roots: the JBP roots, and a set of Kokonoe roots. It appears to have ground layered. No one knows if it was intensional, or a happy accident. At any rate, the JBP roots have been removed, and the tree is on its own roots.
I have a couple other obscure cultivars that have 1/2 inch needles. REALLY slow growers!
But the point I’m trying to make is the trees I have, none of the JWP are seedlings. They’re all grafts or layers. The needle quality of most JWP seedlings are inferior to the cloned varieties, which is why most of the JWP we see are grafts. Only Kokonoe and Zuisho can be reliably propagated by layering. They can be grown from cuttings, but only 5 percent will live.