Plant of the Month: January

Pinus sylvestris Aurea Group (formerly P. sylvestris 'Aurea') Common name: Golden Scots Pine Family: Pinaceae Vital statistics Height and spread: 10-15m (30-50ft) high Form: Slow-growing evergreen tree Soil: Acidic, well-drained. Aspect: Full sun Hardiness: Hardy throughout the British Isles

Pinus sylvestris Aurea Group @ Rosemoor

There are three good specimens of P. sylvestris Aurea Group at Rosemoor. Two of these are situated in the Winter Garden - an ideal situation, as this is the season when this tree is at its best. The third, a more mature tree, is in Lady Anne's Arboretum just a few yards from the Croquet Lawn Garden.

Pinus

This popular genus consists of evergreen trees and shrubs that have great decorative and commercial value. They grow throughout the northern hemisphere, in Europe, North and Central America, Asia, northern Africa, the Canary Islands, and the Philippine Islands. Most survive in temperate and cold temperatures, but some are suitable only for warm or subtropical climates.

Pinus has two types of leaves. The leaves of seedling trees are soft and produced singly around the shoot but these are replaced after the first year or two by longer and stiffer, sometimes rigid and sharp, needles that are usually arranged in clusters of two to five.

Male and female flowers appear separately but 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 carried by the wind to the female flowers. Fertilisation, however, doesn't actually happen until the next year and 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 bark of Pines can be rough and fissured or smoother and scaly. Pinus sylvestris bark is grey-brown, but peels to show a red-orange colour, especially striking on the upper trunk and branches. The bark peels in thin scales to give a shredded appearance.

The wood of many species of pine is very important commercially. Pines valued for their timber include P. sylvestris (Scots pine), P. nigra (Austrian pine, European black 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 south eastern U.S.A. and the Himalayas, to extract their resin, which is distilled to make turpentine. Pine seeds, or pine kernels, are popular both fresh and roasted and often used in cooking while Pinus rigida (pitch pine) is used as firewood and in the manufacture of charcoal.

Pinus sylvestris Aurea Group

Members of the Aurea Group have been in cultivation since 1876 and are grown for their wonderful golden winter colour. The colder the weather becomes, the more golden the foliage becomes. In warmer weather the needles are a more bluish-green, but usually retain a lemon-yellow tint at the tips, giving an interesting colour combination.

The tree grows slowly when young, and so is sometimes considered a semi-dwarf, but it can grow in the region of 15cm (6in) per year when established.

In a garden it is suitable to brighten up a dull area, as long as it is in sun, and makes a fantastic contrast against other, greener foliage in winter. It is a good accent plant, tolerant of relatively inhospitable conditions, and can be useful if cut for flower arrangements.

AGM

The RHS Floral B Committee awarded Pinus sylvestris Aurea Group an Award of Garden Merit and described it as: a slow-growing, small evergreen tree, the foliage bright golden-yellow in winter and spring, later dull blue-green.

Cultivation

Pinus sylvestris prefers a well-drained, acidic soil in full sun. It is very tolerant of infertile and dry soils, and is wind resistant.

Pines in general are susceptible to Diplodia and various needle cast diseases as well as being prone to honey fungus, pine shoot moth, aphids, adelgids and sawfly larvae.

Propagation

Members of this cultivar group should be grafted onto a Pinus sylvestris rootstock in late winter, as seedlings will not reliably come true from seed