Pinus heldreichii Seeds | Bosnian Pine
LATIN NAME: Pinus heldreichii
COMMON NAME: Bosnian Pine
Plant Profile
The Bosnian pine is a tree of high, windy limestone, and everything about it — bark, needles, cone — is built for that exposure. It reaches 20 to 35 metres, though on exposed ridges it stays much smaller and can be a gnarled, storm-shaped shrub. The bark on young trees is pale grey and smooth, and old trees keep that colour far up the trunk, which is why the species was once separated as Pinus leucodermis, the white-barked pine. The needles are in pairs, dark green, stiff, densely packed and marked with white stomatal lines, so that the crown looks almost black from a distance and the branches look frosted close up. The cones are blue-purple when young, turning brown, and they sit in clusters. It grows on limestone mountains from Italy and Bosnia through Montenegro and Albania to Greece and Bulgaria, mostly above 1000 metres.
Science & Biotechnology
Pinus heldreichii and P. leucodermis were described separately and are now universally treated as one species, with the western Balkan and southern Italian populations sometimes recognised as subspecies. The tree is remarkable for its longevity: a specimen in the Pindus mountains of Greece, known as Adonis, has been dated to more than a thousand years, and the species routinely reaches several centuries on exposed limestone where growth is a few millimetres a year. That slow growth makes the wood extremely dense and resinous, and it makes the tree a valuable archive for dendroclimatology, since the rings record centuries of drought and temperature in a region with few other long records. The species is also of interest for its resin chemistry and for its tolerance of alkaline soils, which is unusual among pines.
Uses & Benefits
It is planted as an ornamental in Europe and North America, where its dense dark crown, its tolerance of limestone and wind, and its slow, compact growth make it a good specimen for a rock garden, a large border or a windy site. It is also used in shelterbelts and in reforestation on dry limestone in the Balkans, where few other conifers will establish. The wood is hard, heavy and resinous and is used locally for construction and fuel, though the tree is too slow and too scarce to be a timber crop. The resin has been collected in small quantities for local use. In a garden it is one of the best pines for a small space, because it grows slowly and keeps its shape without pruning.
Growing from Seed
The seed needs cold, moist stratification for four to six weeks; sow in autumn and leave the pot outside, or stratify and sow in spring at 18 to 20 °C. Germination is usually good and the seedlings are sturdy but slow. Grow them in full sun, in a gritty mix with plenty of limestone or grit, and water sparingly — this is a pine that resents rich, wet compost. Pot on into deep containers and plant out at two or three years, in autumn, on a site with sharp drainage and full sun. Once established the tree needs no irrigation and no feeding, and it is hardy to about minus 25. Do not prune the leader; if the tree needs shaping, pinch the candles in spring rather than cutting into old wood.
Our Take
A slow, dark, long-lived pine for limestone and wind, and one of the best conifers for a garden that cannot offer rich soil.
Related Reading
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