January Plant Profile: Juniperus morrisonicola
Scientific Name: Juniperus morrisonicola
Common Name: Yushan Juniper
Family: Cupressaceae
Native Range: Taiwanese mountains
Location in the Arboretum: There are 8 of these trees in our collection; all accessioned in 1938. Seven are located within the Pinetum area and one is located at the north end of Crabapple meadow.
The Yushan Juniper is an elegant conifer native to a small area of the Taiwanese mountain ranges, which are the tallest mountains in Southeast Asia. Because of their remote location and rarity these trees have not had many studies done on them and do not currently have a conservation status assigned. These Junipers have in the past been treated as Juniperus squamata var. morrisonicola, but recent DNA work has indicated it should probably be treated as its own species. The species name Morrisonicola is derived from the British colonial name for Yushan, which was Mt. Morrison.
Yushan, or Jade Mountain, is a National Park in south central Taiwan which covers only 3% of Taiwan’s land area but is home to more than half of Taiwan’s native plants, including 27 species of conifers.
The Yushan Junipers in this range live in coniferous cloud forests at an elevation of between 3,100 and 3,600 meters (about 11,500 feet) in what is called the sub-frigid zone just below the alpine vegetation belt.
The temperature on Yushan stays at 50 degrees Fahrenheit or below all year round, and the main peak is snowcapped from late December to April. The name “Jade Mountain” derives from the clean, white peak of wintertime.
The rock of Yushan is composed of metamorphic sandstone and shale distributed along sharp precipices littered with scree. The Junipers that stand alone along the top margins of these slopes tend to grow in stunted, gnarled forms reminiscent of the ancient bristlecone pines the US Sierra Nevada range. If the junipers grow in groups, or Copses, in protected areas they tend to be more shrublike.
It is estimated that the trees can grow up to 30 feet tall. The Yushan Junipers in the Washington Park Arboretum are at least 86 years old and growing in a milder climate than their native environment, have reached about 15-20ft in height.
The Yushan Juniper has lateral, gently U-shaped branches, whose ends droop with tufts of awl-shaped needles reminiscent of clumps of moss. The tree also has exfoliating reddish bark and a triangular habit. The trees seem to be disease free and adapt well to our temperate climate in Seattle.
References:
Junipers of the World, 2004, R.P. Adams, RGB Edinburgh, 2019, World Flora Online, 2024)
Gymnosperm Database:
https://www.conifers.org/cu/Juniperus_morrisonicola.php
Yushan National Park Service:
Magnifissance:
https://magnifissance.com/arts/juniper-tree/