Swiss Stone Pine Tree Facts

Description

• Swiss stone pine trees are coniferous evergreens with dark green needles reaching 2 to 5 inches long in bundles of five. These needles stay on the tree for about five years before they are shed. These trees produce tiny blooms and release pollen in the wind from May to June. After maturing for 30 years, the Swiss stone pines begin producing 2 1/2-inch-long purplish cones, which take three years to mature. The cones never open and are full of edible pine nuts. The cones in their natural habitat are torn apart by wildlife, releasing the seeds.

Growth

• These trees can put on 12 inches of growth per year when planted in good growing conditions but are considered a slow-growing conifer. Swiss stone pine trees grow well as bonsai trees, staying small for an extended time. While the trees are young, they naturally grow in a pyramid shape without trimming. The shape becomes more columnar as the trees age. In cultivation, they commonly reach 30 to 40 feet tall and 15 to 20 feet wide. They are known to reach 100 feet in their natural habitat.

Growing Conditions

• Swiss stone pine trees grow best in full sun locations in U.S. Department of Agriculture plant hardiness zones 4 through 7. In warm climates, these trees tolerate light shade during hot afternoons. Plant the pine trees in well-draining soil. They prefer sandy soil, but will tolerate heavy clay and poor soil. These trees work well as wind breaks, tolerating strong winds. These trees do not tolerate the salty conditions associated with growing near the ocean.

Pest Information

• The only true pest for these trees is aphids. Aphid infestations may be controlled by spraying the branches with a strong stream of water while the tree is short enough to reach with the hose. For taller trees, release predatory insects like ladybugs near the tree. The Swiss stone pine trees resist root rot, verticillium and blister rust.