How to Grow and Care for Jeffrey Pine

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.

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.

Light

Jeffrey pine needs six or more hours of direct sunlight. It will not grow in the shade.

Soil

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.

Water

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.

Fertilizer

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.

Pruning

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. Pruning in spring is not advisable; it is best to prune in fall or winter when most pests are dormant. 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.

Overwintering

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).