Stone Pine, Pinus Pinea, is a multi-flush pine, two-needle pine. Some report P. Pinea is capable of 3 flushes of growth under optimal “Mediterranean” conditions. The Pinea will push juvenile growth, which is blue in color, through adventitious buds on a strong tree when pruned back into woody growth provided there is still mature needles present. Some cultivate the tree using techniques to foster juvenile growth because they feel the mature needles are too long. I have grafted 3 JPB scions on to P. Pinea in the fall but I found the grafts to be generally weak. After cultivating the tree for 3 years I’ve found the needles reduce nicely through building ramification and the light green color is really attractive; I ultimately removed the grafts. The mature needles are soft and slender and seem to have a thin cuticle when compare to JBP. The soft needles can make wiring tedious.
They produce flaky bark rather young, and the branch collars at the trunk can swell significantly on vigorous branches. The swelling produces a doughnut shape on the trunk which I think is ugly. As the trunk thickens and bark matures this feature “disappears” but I would want to be sure to remove branches that are too big for the composition as early as possible and utilize energy balancing techniques on trees in development to mitigate the collar swelling tenancies of this species.
The wood is rather supple and branches can be bent like JBP.
They seem to be tolerant of significant root reduction, but I have only dug one large tree out of a landscape and re-potted another from a #5 container into a bonsai pot; both survived, with the latter showing significant slowing of growth after the major root reduction. I also pruned the tree in the fall after re-potting in the spring - this is not something we want to do to trees in general but I was half-way between not knowing any better and experimenting based on what I read about P. Pinea.
In my area, my trees can get wooly aglids which don’t seem to go after my JPB on the same bench, but they like P. Pinea. If left unchecked infestations will cause sooty black mold and branches will start to die back. I use chemical spray to knock down the pest when they appear.