The name of this place is given to the arboretum’s oldest tree, The ‘old hemlock’. It is a 99-year-old (2025) mountain hemlock, Tsuga mertensiana, which was 50 years old and one meter tall when it arrived at the arboretum in the early 1980s. The mountain hemlock can grow 30-40 meters high and often grows into a shrubby form. The bark is dark grayish to reddish brown and the needles, which are normally 10-25 mm long and grayish white, grow in bunches from the shoots.
The normal range of mountain hemlock is northwesternmost North America from British Columbia and Alaska southward along the coast down to California at high elevations (up to 3000 m).
Tsuga mertensiana is usually found in cold, snowy, alpine or subalpine places. It is a slow grower and specimens have been found more than 800 years old. Mountain hemlock grows on most soils but prefers organic soils with a low pH value. The specimen in the arboretum comes from the experimental planting on the Avardo mountain in Jämtland. Here in Baggböle our hemlocks grows together with douglas fir (Pseudotsuga menziesii), tamarack (Larix laricina) Rocky mountain maple (Acer glabrum), and blue spruce (Picea pungens).