Longleaf Pine (Pinus palustris)

Long-leaf Pine, Longleaf Pine, Southern Pine

Pinus palustris is a coniferous evergreen tree known for its long, straight trunk and a crown of dark green needles. This species is a keystone of the Southeastern pine forests and is particularly adapted to thrive in fire-prone environments. The longleaf pine is recognized for its high resin content, which historically made it a valuable resource for the production of naval stores.

I. Appearance and Characteristics 

The longleaf pine (Pinus palustris) is a pine species native to the Southeastern United States, found along the coastal plain from East Texas to southern Virginia, extending into northern and central Florida. In this area it is also known as “yellow pine” or “long leaf yellow pine”, although it is properly just one out of a number of species termed yellow pine.

The tree is a cultural symbol of the Southern United States, being the official state tree of Alabama. This particular species is one of the eight pine tree species that falls under the “Pine” designation as the state tree of North Carolina.

The bark is thick, reddish-brown, and scaly. The leaves are dark green and needle-like, and occur in bundles of mainly three, sometimes two or four, especially in seedlings. They often are twisted and 20–45 centimeters (7+3⁄4–17+3⁄4 inches) in length. A local race of P. palustris in a cove near Rockingham, North Carolina, have needles up to 24 inches (61 centimeters ) in length. It is one of the two Southeastern U.S. pines with long needles, the other being slash pine.

The cones, both female seed cones (ovulate strobilus) and male pollen cones (staminate strobilus), are initiated during the growing season before buds emerge. Pollen cones begin forming in their buds in July, while seed conelets are formed during a relatively short period of time in August. Pollination occurs early the following spring, with the male cones 3–8 cm (1+1⁄4–3+1⁄4 in) long. The female (seed) cones mature in about 20 months from pollination; when mature, they are yellow-brown in color, 15–25 cm (6–9+3⁄4 in) long, and 5–7 cm (2–2+3⁄4 in) broad, opening to 12 cm (4+3⁄4 in), and have a small, but sharp, downward-pointing spine on the middle of each scale. The seeds are 7–9 millimeters (1⁄4–3⁄8 in) long, with a 25–40 mm (1–1+5⁄8 in) wing.

Longleaf pine takes 100 to 150 years to become full size and may live to be 500 years old. When young, they grow a long taproot, which usually is 2–3 meters (6+1⁄2–10 feet) long; by maturity, they have a wide spreading lateral root system with several deep ‘sinker’ roots. They grow on well-drained, usually sandy soil, characteristically in pure stands. Longleaf pine also is known as being one of several species grouped as a southern yellow pine or longleaf yellow pine, and in the past as pitch pine (a name dropped as it caused confusion with pitch pine, Pinus rigida).

The longleaf pine is the official state tree of Alabama. It is referenced by name in the first line of the official North Carolina State Toast. Also, the state’s highest honor is named the “Order of the Long Leaf Pine”. The state tree of North Carolina is officially designated as simply “pine”, under which this and seven other species fall.

II. How to Grow and Care

Sunlight

The longleaf pine can grow in both full sun and partial shade. When placed in a well-ventilated location with sufficient sunlight, the needles will be green and strong. In a hot location with insufficient sunlight, the needles will be weak and will easily turn yellow. Ideally, the plant needs around 5-6 hours of sunlight a day, with good ventilation.

Temperature

The longleaf pine is mostly native to the northern hemisphere and can withstand many challenging environmental conditions. Tolerant of temperatures ranging between -60 to 50 ℃, making it suitable for hardiness zones 11 and below, this is a plant that grows best in well-drained, deep and moist soil.

Watering

For newly planted seedlings or new plants, water once every morning and evening during hot spells in the summer. Do not water midday, as this can cause root burn or strangle. Water plants according to your individual climate and rainfall in other seasons. For mature plants, only water when they are dry, keeping in mind that these plants are drought resistant. For indoor potted plants, spray water on the surfaces of the leaves once every morning and evening when it is dry. Be careful not to provide excess water – this hinders air circulation in a pot, leading to the rotting of roots and the withering of branches and leaves.

Soil

Longleaf pine can grow in a variety of different soil types, including bare mineral soil, sandy soil, volcanic ash, calcareous soil, limestone soil, and everything from dusty soil to red soil. Since it is resistant to drought, it will even grow in barren landscapes. However, it grows best in loose, fertile, well-drained, and slightly acidic soil. In the case of too much alkalinity, needles of potted plants will turn yellow and fall, so it is best to use natural mountain soil in pots and containers.

Fertilizing

The tree does not require fertilizer and does better without. Instead, scatter a layer of compost around the tree every spring and make sure to keep it free from weeds to avoid competition for nutrients.

Planting Instructions

Longleaf pine is best planted in early spring. Ideally, use healthy and vigorous seedlings with soil balls, as this can greatly improve the survival rate. In the case of many lateral roots, the deep main root can be cut. Otherwise, the root system should be protected to avoid damage.

plant in a high, dry, well-drained, and well-ventilated place, with loose soil. In low-lying places with accumulated water, or places with sticky soil, try building a platform or changing the soil before planting. The planting pit should be treated with a basal fertilizer before planting. Newly planted large seedlings should be supported to prevent them being blown down by the wind. Before planting, excess branches should be pruned off.

Protect the plant’s shape from damage as much as possible, as this will help to restore growth at a later stage.

Ideally, plant indoor potted plants in the spring, and repot every two or three years in the late fall or early spring. Repotting too frequently will lead to the death of the plant. If the plant is growing weakly, find out the cause of this and change the flowerpot soil, or replant in a larger pot.

Cut back on water before repotting, so as to keep the soil slightly dry. Remove the soil ball from the pot, keeping it whole, and then prune away any old roots from the bottom and sides. Remove some of the old soil from the middle of the soil ball, replace with new soil, apply a small amount of basal fertilizer, and then cover the plant with new soil. Ensure a suitable pot size – a deep pot will easily accumulate water, leading to root rot.

Pruning

For an indoor potted plant, any dead, diseased or damaged branches should be removed. You can then adjust the tree’s shape by pruning branches, pinching buds, and trimming leaves, giving you a better ornamental effect. Prune the plant before all of its needles fall off, so as to obtain a compact shape, richer lateral and side branches, and a better form overall. Pruning should be done during the dormancy period, so as to prevent excess loss of sap and damage to the plant’s vigor.

For a plant in a garden, dense lateral branches should be pruned so as to improve the survival rate. Remove excess lateral branches during the vigorous growth period based on needs, focusing on encouraging the trunk to grow tall and straight. Cut off any diseased or dead branches right away, so as to prevent the spread of pathogens.

Propagation

Because longleaf pine spends almost its first decade in a grass-like state, it takes a very long time until you see it grow into a sizable tree. Vegetative propagation methods yield mixed results and seeds deteriorate rapidly. For those reasons, if you would like to plant a longleaf pine, it is best to purchase a container-grown seedling.

Overwintering

If planted within its zone range (USDA Hardiness Zones 7 to 9), no particular precautions need to be taken to overwinter longleaf pine

Pests and Diseases

Longleaf pine is one of the most disease-, pest-, and fire-resistant southern pines.

Potential pests of longleaf pine include pine bark beetles, borers, sawflies, pine-shoot moths, and pine weevils. An infestation with bark beetles may manifest itself as needle loss. Generally, pests are more likely to attack trees that are stressed. For this reason, even though longleaf pine is relatively drought-resistant, be sure to water it during dry periods and avoid inflicting mechanical injuries on your tree, such as during mowing, because wounds are an open invitation to pests and diseases.

III. Uses and Benefits 

Vast forests of longleaf pine once were present along the southeastern Atlantic coast and Gulf Coast of North America, as part of the eastern savannas. These forests were the source of naval stores – resin, turpentine, and timber – needed by merchants and the navy for their ships. They have been cutover since for timber and usually replaced with faster-growing loblolly pine and slash pine, for agriculture, and for urban and suburban development. Due to this deforestation and overharvesting, only about 3% of the original longleaf pine forest remains, and little new is planted. Longleaf pine is available, however, at many nurseries within its range; the southernmost known point of sale is in Lake Worth Beach, Florida.

The yellow, resinous wood is used for lumber and pulp. Boards cut years ago from virgin timber were very wide, up to 1 m (3.3 ft), and a thriving salvage business obtains these boards from demolition projects to be reused as flooring in upscale homes.

The extremely long needles are popular for use in the ancient craft of coiled basket making.

Annual sales of pine straw for use as mulch were estimated at $200M in 2021.

The stumps and taproots of old trees become saturated with resin and will not rot. Farmers sometimes find old buried stumps in fields, even in some that were cleared a century ago, and these usually are dug up and sold as fatwood, “fat lighter”, or “lighter wood”, which is in demand as kindling for fireplaces, wood stoves, and barbecue pits. In old-growth pine, the heartwood of the bole is often saturated in the same way. When boards are cut from the fat lighter wood, they are very heavy and will not rot, but buildings constructed of them are quite flammable and make extremely hot fires.

The seeds of the longleaf pine are edible raw or roasted.

Longleaf Pine (Pinus palustris) Details

Common name Long-leaf Pine, Longleaf Pine, Southern Pine
Botanical name Pinus palustris
Plant type Native Plant
Hardiness zone 7b, 8a, 8b, 9a, 9b
Growth rate Fast
Harvest time Fall
Height 60 ft. 0 in. - 120 ft. 0 in.
Width 60 ft. 0 in. - 120 ft. 0 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition Clay
Leaf color Gray/Silver