Stone Pine

Stone pines, or pinyon pines, are commonly used as live Christmas trees and they produce delicious (and expensive) pine nuts.

As far as conifers go, the stone pine is my favorite, simply because of the pine nuts they produce. No pesto is the same without the sweet, nutty flavor of pine nuts. They make scrumptious pine nut bars, too! ​

Mature stone pine in Italy with flatter crown (Kofler Jürgen) CC BY-SA 3.0

Stone pines (Pinus pinea) were originally from northern Africa and are now found in the Mediterranean. People have been enjoying pine nuts since, well, since there have been people! We have actively cultivated these high protein treats for over 6,000 years.

Holiday stone pines

If you received a live pine tree over the holidays, it may very well have been a stone pine. These small containerized trees can ultimately reach 100 feet in height, though most are only 35 to 55 feet tall. If you decide to install your stone pone in the landscape, keep that mature size in mind - moving a full-sized tree is expensive and dangerous! Stone pines can be grown in containers, which limits their size, and they can even be used as bonsai.

​How stone pines grow

Immature potted stone pine

Like most conifers, stone pines grow from seeds found in a cone. This makes them gymnosperms. Stone pine seeds take 3 years to form - longer than any other pine. As juveniles, stone pines are bushy and round, with a bluish tint. The needles are short (3/4 to 1-1/2 inches long) and singular. As trees reach 4 or 5 years of age, mature needles begin to emerge. These older, darker needles are longer (7 to 8 inches long), and held in bundles of 2, 3 or 5. By the time the tree is 10 years old, all the needles will be the longer variety, unless the tree is responding to an injury. Mature trees have an umbrella shape, with a canopy that can reach over 25 feet. They are sometimes called umbrella trees for this reason. They are also known as Italian stone pines. Stone pines prefer full sun and well-drained soil. Once established, they rarely, if ever, need any irrigation, pruning, or fertilizer.

Stone pine pests & diseases

The western conifer seed bug, aphids, pine shoot moths, bark beetles, Eriophyid mites, mealybugs, weevils, and adelgids (an aphid cousin) are common pests. Many of these pests feed on the sap, stealing valuable nutrients and moisture from the trees, causing distortion, susceptibility to other diseases, and even death to the tree. Honey fungus, or Armillaria root rot, Pine needle cast, canker diseases, Botrytis blight, needle blight, root rot, crown rot, and rusts are common pine diseases. 

Fair warning

​Before you jump to buy yourself a stone pine tree with visions of pine nuts dancing in your head, you need to understand that there is a reason why pine nuts cost about the same, per pound, as your finest cut of beef. Getting those nuts to the point where they are edible is very labor intensive. Also, your stone pine will not produce edible seeds until it is 10 to 12 years old. As green cones begin to open, you will need to smash the bejeezus out of them to get the cones to release the nuts. This is commonly done in burlap sacks with baseball bats. Then you get to hand sort through all that pine cone debris to find the dark paper-coated pine nuts. That dark paper is yet another layer that must be removed. This takes a lot of time and patience, and is why most of our $19 a pound pine nuts come from China, where cheap labor makes it financially feasible. Unfortunately, the variety of stone pine grown in China (Pinus armandii) has been shown to leave a metallic taste in your mouth that can last for a couple of days.

So maybe all that time and effort is worth it after all…