Jeffrey pine is a large tree that requires ample growing space, not only because of its height—one of the Jeffrey pines on the California Big Tree index is 184 feet high, with a trunk circumference of more than 24 feet and a crown spread of 69 feet—but also because of the extensive root system that allows it to adapt to poor soils. The bluish-green, silver, or gray needles are 7 to 11 inches long, and the egg-shaped to cylindrical cones measure 6 to 9 inches long. Jeffrey pine can survive in harsh conditions and is an important tree in the lumber industry. It makes for a good landscape specimen for very large landscapes, as its lowest branches tend to be quite high above the ground.
This tree is normally planted as a container-grown specimen or balled-and-burlapped plant in the fall or spring. It is a relatively fast-growing conifer (2 to 3 feet per year) and extremely long-lived—Trees that are centuries old are common.
|Common Name||Jeffrey (Jeffrey's) pine|
|Botanical Name||Pinus jeffreyi|
|Plant Type||Coniferous tree|
|Mature Size||80–140 ft. tall, 25–35 ft. wide|
|Sun Exposure||Full, partial|
|Soil Type||Loamy, sandy|
|Soil pH||Strongly acidic to neutral (5.2–7.0)|
|Hardiness Zones||5–9 (USDA)|
|Native Area||Western North America (California, Oregon, Nevada)|
Jeffrey Pine Care
The most important thing you need if you want to grow Jeffrey pine is space. It will grow fairly quickly at 2 to 3 feet per year, exceeding 50 feet within 20 years, so give careful thought to where you plant it. This tree does well even in harsh conditions, but does not do well in warm weather, nor does it like the alkaline soil conditions found near the coast It is most often found growing naturally on dry, rocky slopes at mid-elevation mountainous regions, so is best suited for landscape settings that mimic this. In areas with strong, steady winds, it sometimes takes a windswept, sculptural shape; elsewhere, it grows a tall, upright specimen.
Grow the tree in full sun and don't worry about watering for established trees; this tree is quite resistant to drought.
Jeffrey pine needs six or more hours of direct sunlight. It will not grow in the shade.
It can grow in moist to dry soil, and in highly acidic to neutral soil pH, but the ideal is a loamy soil. Any soil that provides excellent drainage is good. Though gravel or rocky soil will work, it is not preferred.
The tree is highly drought-tolerant and does not require watering unless in periods of extended year-long drought.
Temperature and Humidity
Jeffrey pine adapts to cold weather with a short growing season. Wide climate extremes, like those that occur in mountainous areas, are not a problem for this tree. It prefers cool summers and does not tolerate the hot and humid climates of coastal areas or the South.
Like many native plants, Jeffrey pine does not require fertilizer. It can grow in nutritionally poor and even infertile soil because it has an extensive, hardy root system.
Types of Jeffrey Pine
The pure species plant is most common in the trade, but there is one popular cultivar, 'Joppi', which is a dwarf, globe-shaped variety.
Your tree won't need much in the way of pruning. Pine trees of all kinds tend to grow in a neat, orderly fashion. However, pruning away dead or damaged branches is a must. You should also prune away any branches that rub against each other. It's best to do this in the spring, which gives the bark time to heal before winter. Cut damaged branches all the way back to the collar, right next to the trunk of the tree.
Propagating Jeffrey Pine
Jeffrey pine grows so well through seed distribution that propagating through cuttings is not only unusual but also quite difficult.
How to Grow Jeffrey Pine From Seeds
Cone-bearing Jeffrey pines produce seeds every two to eight years. These winged seeds drop from the tree and readily germinate and take root. When growing a sapling from seed, remember that they must have at least 60 days of cold stratification in order to germinate in the spring. To that end, keep them in a cold place, such as your refrigerator, until early spring. In nurseries, the seeds are often sown in April for the earliest strong saplings. When starting indoors, it typically takes only one growing season for a seedling to reach the appropriate size for planting, but some gardeners wait for two seasons, to ensure the growth of a strong taproot that will take hold in the ground quickly and prevent wind damage.
Jeffrey pine is quite cold-hardy and as such can handle harsh winter conditions just fine. Though it might be beneficial to provide small saplings with mulch over their roots, this is certainly not a deal-breaker; the trees should grow just fine in the spring without winter's protection.
Common Pests and Plant Diseases
The most serious insect threat is the Jeffrey pine beetle (Dendroctonus jeffreyi). While beetle populations are often present, they cause the most damage and kill trees in periods of severe or extended drought. It’s usually only when the green crowns fade to yellow and reddish-brown that the beetles are detected. The best way to prevent Jeffrey pine beetle attacks is to water the tree during severe and extended droughts to keep it healthy. Other pests are aphids and beetle borers such as the California flathead borer.
Possible diseases include the fungi armillaria, phytophthora root rot, Western gall rust, and needle cast. Jeffrey pine can also be affected by mistletoe, a semiparasitic plant.
Common Problems With Jeffrey Pine
While Jeffrey pine has a good tolerance for harsh weather conditions, it can be sensitive to air pollution, especially high ozone levels, which can cause needle death and defoliation. If these symptoms occur, it is likely the tree's reaction to poor air quality.
Jeffrey pine serves as a common host for parasitic mistletoe, which can grow to a size that can break branches on younger trees. The most common holly is dwarf mistletoe (Arceuthobium campylopodum).
What is the difference between Jeffrey Pine and Ponderosa Pine?
There are two ways you can distinguish these two large trees from each other.
First, by the cones: The cones of the ponderosa pine have scale barbs pointing outwards. The cones of the Jeffrey pine, on the other hand, have their scale barbs pointing inward, so they are much more pleasant to the touch.
Second, by the bark: When you break off a piece of the deeply furrowed, flaky, cinnamon-colored bark of the Jeffrey pine during the growing season, it exudes an aromatic smell that is compared to lemon, vanilla, pineapple, violet, or butterscotch.
How long can Jeffrey pine live?
A life span of 150 years and beyond is not unusual. The most famous Jeffrey pine grew on Sentinel Dome in Yosemite Park in solid granite without soil. The seed was probably dropped there by a bird, and the tree rooted in a crack of the granite rock. Carleton Watkins photographed the Jeffrey pine in 1867, and Ansel Adams immortalized the tree in his famous photograph from 1940. When the tree died during a severe drought in 1976 and 1977 and finally fell over in 2003, it was supposedly more than 400 years old.
Can Jeffrey pine grow indoors?
Surprisingly, given the Jeffrey pine is a very large tree, it makes a good specimen for bonsai. If you intend to use your Jeffrey pine as a bonsai, expect to keep it indoors, and train it regularly to keep a compact, unique shape.
How did this tree get its common name?
Jeffrey pine is named for discoverer John Jeffrey, a 19th century Scots botanist who found the tree in the Shasta Valley of California.