Pond pine is a medium-sized tree characterized by its twisted needles that group in threes, and a preference for wet, acidic soils often found in swampy areas. Its barrel-shaped cones open late, hence the species’ designation related to lateness. The dark, scaly bark and ability to thrive in periodic standing water make pond pine resilient in its habitat.
I. Appearance and Characteristics
Pinus serotina, the pond pine, black bark pine, bay pine, marsh pine, or pocosin pine, is a pine tree found along the Southeastern portion of the Atlantic coastal plain of the United States, from southern New Jersey south to Florida and west to southern Alabama. Pond pine distribution may be starting to spread west towards Mississippi and Tennessee.
Pinus serotina was described in 1803 by Andre Michaux. Pinus is a large genus of evergreen conifer trees. The species name serotina is derived from the persistently serotinous cones that may remain closed for several years before they release their seeds. Historically this species has been viewed as a subspecies of Pinus taeda. Similarly Pinus serotina has also been considered a subspecies of Pinus rigida (Pinus rigida subsp. serotina (1880)).
This pine often has a crooked growth pattern and an irregular top and grows up to 21 meters (69 ft) high, rarely to 29 meters (95 ft).The needles are in bundles of three or four, and 15–20 cm (6–8 in) long. Pinus serotina will grow needles and little branches directly from the trunk, similar to the Pinus rigida (pitch pine), but the pitch pines will only grow in drier areas. The Pinus serotina is very similar to the common Pinus taeda (loblolly pine), but the key differences are they have direct needle growth from the trunk, are smaller in size, and tend not to grow straight. The bark of the pond pine forms rough plates. They are a brownish-red color.
The pond pines are not as cold hardy as the loblolly and pitch pines. It takes 18 years for the pond pine to reach full maturity. The almost round cones are 5–8 cm (2–3+1⁄4 in) long with small prickles on the scales. Its cones are usually serotinous, requiring fire to open. The pollen cones are cylinder-shaped with a yellow, brownish color, and are up to 1.8 inches long.
Seed cones need two years to mature after pollination. In some cases, they will drop their seeds, but in most Pinus serotina, they will persist and hold their seeds. The color of the seed cones and seed scales is red-brown in color. The foliar sheaths measure 0.4 to 0.8 with long bases.
The seeds are ovule in shape, being 0.2 and 0.24 in length, and have an angled tip colored a pale brown. For seeds to be used for regeneration, seed trees that are 23 to 25 cm (9 – 10 inches) in DBH and 30 years old are expected to produce 5,000 seeds.
Pinus serotina stands provide habitat and support for many wildlife species, particularly for birds and mammals in wetlands and flatland environments. The pond pine is intolerant of shade. In order for reproduction to occur, Pinus serotina needs fire in the form of intense scorching or defoliation. The buds are dormant and protected by the tree’s thick bark. When parts of the tree are top killed by fire, epicortical buds can resume growth. 15 to 20 seed trees are needed per hectare (6 to 8 acres) for the sufficient seed set after fire. Without the heat from a fire the seed fall is limited by the serotinous cones of pond pine.
Pond pine seedling growth is often limited by the moisture in the soil, lack of nutrients, and competition. Under poor growing conditions pond pine seedlings grow can as little as 30cm (12 inches) or less per year.
II. How to Grow and Care
Sunlight
The pond 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 pond 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
Pond 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 pond pine likes fertilizer and should be fertilized frequently, with just a small amount each time, during its growth period. It should be fertilized once a month in late spring, early summer, and fall. A fermented organic fertilizer is most effective for promoting growth.
Generally, do not apply a nitrogen fertilizer, such as urea or human urine, because pine needles already absorb nitrogen from the air, and pine roots are sensitive to nitrogen. You would be best off with a liquid fertilizer, applying this when the soil is dry in the afternoon. Water the plant again after fertilizer application, which will help with root absorption.
Do not use fertilizers that haven’t been fermented, or those with a higher concentration; the former will burn the roots and the latter will lead to the spindling of needles and more root damage, and could even cause the back-flow of sap, leading to water loss and the withering of the plant. No fertilizer should be applied in midsummer, during severe winters, or in the rainy season in the spring.
Generally, plants in gardens should be fertilized twice during the growth periods in spring and fall. Apply an organic fertilizer once before germination in the spring and apply slightly more fertilizer in the fall to promote robust growth. Stop fertilizing after midsummer so as to prevent spindling.
Planting Instructions
Pond 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
Pond pine is mainly propagated by seeds or branch cuttage. For family planting or potting, cultivated seedlings or pruned potted plants can be purchased from the market. Pay attention to pests, diseases, and appearance when selecting seedlings.
Pests and Diseases
Several species of bark beetles attack southern pines including pond pine, the beetles include the Southern pine beetle, three species of the Ips engraver beetles, and the black turpentine beetle. These beetle species grind through conducting tissues of their hosts. Phloem damage leads pine needles fading from green, to light green, and death of the tree. These trees also face the eastern pine weevil and are susceptible to wind damage. Pinus serotina also faces red heart disease (Phellinus pini), a fungal disease of pines.
III. Uses and Benefits
Even though the Pinus serotina has poor form and relatively slow growth, it can produce economically valuable tree stands of pulpwood and saw timber where other trees will not grow. Tan or green dyes can be obtained from the needles of the Pinus serotina. A vanillin flavoring is obtained from the byproducts of the pulpwood’s resins. It is suggested that Pinus serotina might be a valuable remedy to treat the kidney, and can be administered as a rub or in a steam bath. Pinus serotina may be useful in treating diseases of the mucous membrane and respiratory complaints.
