Tsuga diversifolia - northern Japanese hemlock

The hemlock (Tsuga) genus gets its scientific name from the Japanese word tsuga. The northern Japanese hemlock is one of the two hemlock species native to Japan, and its natural habitat is the mountains of Honshu Island between 900-2200 metres, approaching the tree line. On the best sites it reaches heights of 25 metres but higher up the slopes remains a low shrub. Compared with other hemlocks the crown is exceptionally dense and broad, reminiscent of broadleaf trees. On their undersides the needles are strongly silver-white, of varying length, broad and notched at the tip. In good seed years the branches are covered in slim fingertip-sized cones.

Groups of handsome old northern Japanese hemlock are found in scenically important places in the Mustila landscape. The first specimens were obtained by A. F. Tigerstedt from St. Petersburg in 1906 as 6-year-old seedlings. The latest plantings are plants grown from seed received from Japan in 1991, which were collected in the Kiso Valley in Nagano prefecture. Despite having developed into handsome trees at Mustila, these natives of a maritime climate aren’t completely winter-hardy. In exceptionally cold winters they suffer needle damage, and some large trees have even died, most recently during the hard winters of the 1980s.