Pinus luchuensis Seeds | Luchu Pine
LATIN NAME: Pinus luchuensis
COMMON NAME: Luchu Pine
Plant Profile
The Luchu pine is a two-needle pine of fifteen to twenty-five metres with a broad, flat-topped crown and cones that are small, chestnut-brown and almost round. It grows on the islands between Kyushu and Taiwan, from sea level to the hills, and it is the pine of the Okinawan coast.
It is closely related to the Japanese black pine and hybridises with it where the two are planted together, which makes identification in a garden uncertain. In Okinawa it is planted as a windbreak and as a shade tree, and its seed is collected locally for reforestation of the coastal hills. The bark is grey-brown and scaly, and the tree bleeds resin freely from a wound, which is how the local timber trade identifies it.
Science & Biotechnology
The species is one of the pines that tolerate salt wind, and its needles are short and stiff enough to shed the spray without scorching. It grows on coral limestone, where the soil is thin and alkaline, and it depends on mycorrhizal fungi to obtain phosphorus in that ground.
Pine wilt disease, carried by the sawyer beetle and caused by a nematode, has killed millions of Japanese red and black pines. The Luchu pine is generally less affected than those two, and it has been used in breeding work as a source of tolerance, though it is not immune and infected trees die within a season.
Uses & Benefits
The wood is hard, resinous and durable, and it is used in Okinawa for construction, for boats and for the posts of traditional houses. It is also cut for charcoal, and the charcoal of the Ryukyu Islands was a trade good before the modern era.
The tree is planted as a windbreak along the coast and as an ornamental in subtropical gardens, where its flat crown and its tolerance of salt make it useful. It is also used for bonsai and for garden pines in Japan, though it is less common in that role than the black pine.
Growing from Seed
Sow seed in spring after sixty days of cold moisture, on the surface of a well-drained mix at twenty degrees. Germination takes three to four weeks, and the seedlings need full light from the start or they etiolate.
Plant out in sun on soil that drains, and do not enrich the ground, since pines in rich soil grow soft and are damaged by wind. Water for the first two summers, then leave the tree to find its own water. In a container use a gritty mix and repot every third year, since the roots resent disturbance. The tree also regenerates from seed on bare coral rock after fire, and the seedlings need the shade of a nurse shrub for the first year.
Our Take
A salt-tolerant pine for a coastal garden and a useful windbreak tree, less tender than its tropical looks suggest. Give it drainage and full sun.
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