Pinus

This popular group consists of evergreen trees and shrubs that have great decorative and commercial value. They grow throughout the Northern Hemisphere. Some are found in Europe, North and Central America, Asia, northern Africa, the Canary Islands, and the Philippine Islands. Most of them survive in temperate and cold temperatures, but some are only for warm or subtropical climates. Pinus is the botanical name for the Pine tree. Pine trees have two types of leaves. The leaves of seedling trees and up to a year or two are soft and produced singly surrounding the shoot. The leaves of the mature tree are longer and stiffer, sometimes rigid and sharp. They are usually arranged in clusters containing from 2 to 5 needles. Each cluster is surrounded at the base by a deciduous sheath. The sheath varies in length, and in some kinds may fall soon after the leaves form, or may remain until the leaves fall, which may be from 2 to 5 years. These characteristics determine the classification of the different varieties. Other characteristics that are taken into account are the closeness of scales, shapes and lengths of the flower buds. Male and female flowers grow on the same tree in spring or early summer. The female flowers are scattered singly or in small clusters along the new shoots; male flowers are ordinarily found near the base of the new growth and they provide large amounts of pollen, which is spread by the wind to female flowers. Fertilization, however, doesn't actually happen until the next year. The female flowers are usually reddish colored, sometimes pale pink or other colors, and they look like tiny cones. It often takes two and sometimes three years for the cones to reach maturity. The cones vary in size, hardness and shape. Usually, cones of two- or three-leaved Pines are more woody than Pines with leaves in groups of five and they are equipped with stiff points; they stay closed longer than the cones with five leaves. The seeds have "wings" and are dispersed by the wind. One of the most well-known Pines of the five-leaved group is the White Pine, P. strobus. This tree is a native of North America. Besides being valued for its beauty, it provides exceptional timber. Under optimum conditions, the White Pine can reach a height of 150 feet. There are many varieties of the White Pine; including those with golden leaves and some that are dwarf. The needles of the White Pine are soft, flexible and bluish-green. Its cones mature at the end of the second season and reach a 4- to 8-inch length. A Pine belonging to the two-leaved group is P. resinosa, the Red Pine. It is one of the hardiest and is found in North America. Its dark green needles are from 4 to 6 inches long. They are thin, straight and flexible. The cones are about 2 inches in length and mature at the end of the second season. The bark is reddish-brown. The Red Pine is often called the Norway Pine even though it doesn't come from Norway. This tree can grow up to 100 feet in height. P. rigida, the Pitch Pine, is a member of the three-leaved group. It is mainly found from Maine to Ontario and Ohio to Georgia, usually on poor rocky soil. The needles are from 2 to 5 inches long, thick, stiff, twisted and yellowish-green in color. The cones mature in the fall of the second season, but often remain on the branches for many years to come. They are about 1� to 3 inches long and are armed with short, hard, points. The Pitch Pine is very resistant to fire and is often the only tree able to survive on repeatedly burned over areas. The maximum height for this tree is 70 to 80 feet. The wood of this Pine is weak, soft and brittle, but is durable when in contact with the soil. It is mainly used as firewood and in the manufacture of charcoal. Old trees are usually quite interesting, with their irregular, scraggly crowns and their gnarled and often drooping branches loaded with persistent cones. More Pines of each group will be mentioned below in the varieties section. The wood of many kinds of Pines is very important commercially. P. echinata (Shortleaf Pine), P. strobus (White Pine) and P. palustris (Longleaf Pine), all eastern American Pines are valued for their lumber. Western American Pines valued for their lumber include P. Lambertiana (Sugar Pine), P. monticola (Western White Pine) and P. ponderosa (Western Yellow Pine). Pines from abroad that are also valued for their timber are P. sylvestris (Scotch Pine), P. nigra (Austrian Pine), P. Thunbergii (Japanese Black Pine), and P. densiflora (Japanese Red Pine). Pine trees are also tapped in several parts of the world, such as western France, the southeastern U.S., and the Himalayas, for the purpose of their resin, which when distilled provides turpentine and resin. Pine seeds of many trees are used both fresh and roasted; they are called Pine Kernals.

Pot Cultivation

Pine trees do best on dry or well-drained soil. They won't survive on waterlogged or sour ground. There are some kinds that will live on wet land, but they don't have great garden importance. Pines don't require rich soil, though they grow well in loam and are often seen luxuriating on sand and sandy peat. Some can be grown at considerable elevations and also at sea level. Only a few kinds will live on alkaline soil. Pines intended to grow in the forest should be set in their positions when quite small, from 9 to 12 inches high. Larger plants can be transplanted into the garden or yard, but it isn't smart to move trees over 3 or 4 feet tall, unless they've been transplanted every 2 or 3 years in a nursery or they've had their roots trimmed a year before transplanting. Pines usually form straggly roots and it's difficult to dig them up with a good soil ball, but this is very important to successful transplanting of all but very small plants. Planting should be done in early fall or spring, just before they begin to grow. Trees for forest planting are usually set into small holes or notches cut into the ground, but for Pines intended as ornamental trees, holes 1� to 2 feet deep and at least 1 foot wider all around than the root ball should be dug. If the location of your Pine is out in the open, tilt the tree a bit into the wind. Until they've become established, stake or support the tree with guy wires to prevent it from loosening at the ground.

Propagation

Seeds should be sown in well-drained soil in April or early May. All danger of late spring frosts must be passed before the seedlings sprout, which may be anywhere from two to five weeks, according to the weather conditions. The seeds should be sown thinly and covered with about a �-inch of sand or light soil. Before planting, roll the seeds in red lead to protect against pests. The ground should never be waterlogged because that will kill the seedlings.