If you have had dishes with pine nuts in Europe, they probably came from the Italian stone pine. In Italy, they are called pignoli or pinoli and were used at least as far back as the Roman Empire. It is one of a few pine tree species from which these seeds are harvested for eating.
The scientific name for this species is Pinus pinea and it belongs to the Pinaceae family. Other relatives besides the pine trees include most of the deciduous conifers (Larix spp.), spruce trees, fir trees, Douglas firs (Pseudotsuga spp.), cedars (Cedrus spp.) and hemlocks (Tsuga spp.)
Besides Italian stone pine or stone pine, it is sometimes called umbrella pine or parasol pine due to its shape.
Preferred USDA Hardiness Zones
This tree will grow best in Zones 8-10. It originally comes from Southern Europe, Turkey, and Lebanon.
Size & Shape
At maturity, the average size of this pine tree species is 30-60' tall and 30-50' wide. Most pine trees form into a pyramidal shape, but the Italian stone pine has a rounded umbrella-like canopy.
This evergreen tree needs to be placed in a location that received full sun.
Each fascicle (bundle) contains two pine needles that are two to four inches long. New growth is formed each spring and is called a conifer candle.
The flowers are a type called strobili and are produced by gymnosperms. The tree is monoecious and both male and female strobili will be present.
Seeds can be gathered from the cones and are called pine nuts, though they are not true nuts. This tree is the main source for these in Europe. Sometimes eating these will cause a phenomenon called pine nut mouth where you have a bad taste in your mouth for days. However, this does go away and scientists have not been able to find medically significant side effects for humans.
You can harvest pine nuts from your trees by collecting cones and placing them in a warm sunny location until they fully open. The seeds may come out on their own, but it is more likely that you will need to use force to break the cone apart and release the seeds. There is a shell that you will have to remove.
Design Tips for the Italian Stone Pine
This is a drought tolerant tree once you have given it a season of adequate watering to help root establishment.
The Italian stone pine offers an alternative shape to many evergreens but still features four season color.
Growing Tips for the Italian Stone Pine
Soil can be acidic, neutral or alkaline and should provide good drainage.
The most common method of propagation is from seed. It can also be grafted or grown from cuttings to preserve cultivar characteristics if needed.
If you are growing this tree for the pine nuts, be aware that it may take many years before cones are produced and then an additional three years for them to mature.
You can use fallen pine needles as a natural mulch to help water retention and keep weeds at bay. Make sure to leave a space of a few inches between the trunk and the mulch. If they touch, this can cause problems like fungal diseases and make it harder for the tree to get oxygen.
There should be little pruning needed unless you need to take care of branches that are dead, diseased or damaged.
Pests & Diseases of the Italian Stone Pine
There are usually not many disease problems found with this species. You may see episodes of pine needle cast, which is a fungal disease that causes the needles to turn brownish-red and fall off. This is usually a symptom of other problems like bark beetles, so check the tree for other pests and diseases.
Possible pests include:
- Bark beetles
- Western conifer seed bug (Leptoglossus occidentalis)