Sciadopitys verticillata, as described in 1842 by (Thunberg) Philipp Franz von Siebold (1796–1866) and Joseph Gerhard Zuccarini (1790–1848), is commonly known as Japanese umbrella-pine, as well as コウヤマキ (koya-maki) in the Japanese language. The English name 'Umbrella-pine' refers to the whorls of leaves resembling the spokes of an umbrella; the Latin Sciadopitys is a translation of this.
Description. Japanese umbrella-pine is an evergreen coniferous species of tree which will grow to mature heights of 65 to 100 feet (20 - 35 m) tall with a trunk up to 3 feet (1 m) in diameter at breast height, growing single- or multi-trunked.
Branching is dense and heavy with luxuriant foliage.
Bark is thick, soft, red-brown and stringy. Leaves are of two types, scale leaves on the stems that are brown, 0.04 to 0.12 inch (1 - 3 mm), widely spaced between the nodes on long shoots, and clustered in a tight spiral pseudo-whorl.
Photosynthetic leaves are variously interpreted as a pair of true leaves fused together, or as highly modified shoots (cladodes). They grow linearly, in pseudo-whorls of 10 to 30 at the shoot nodes and are , 2.5 to 5.5 inches (6 - 13 cm) long, 0.08 to 0.12 inch (2 - 3 mm) wide and 0.04 inch (1 mm). They are thick, heavy, fleshy, pliable, with a prominent mid-line groove on both sides; rich glossy green in color with a pale stomatal line on each side of the mid-line groove on the underside. They persist 3 to 4 years on the tree before being shed.
Pollen cones measure 0.24 to 0.5 inch (6 - 12 mm) long, growing in dense terminal clusters 0.4 to 0.8 inch (1 - 2 cm) across.
Seed cones are ovoid and green in color when young, ripening to dark brown 18 to 20 months after pollination. They measure 1.8 to 4 inches (4.5 - 10 cm) long and 1.4 to 2.6 inches (3.5 - 6.5 cm) wide when open. They are fragile and break up soon after seeds are released.
Distribution. This species is native to Japan — southern Honshu, Kyushu and Shikoku, growing in mixed middle altitude cloud forest forests at elevations of 1,500 to 3,200 feet (500 - 1,000 m) above sea level, with high rainfall and humidity. It forms old-growth forests with Chamaecyparis obtusa. Seedlings can regenerate beneath the forest canopy, although small gaps with exposed mineral soils constitute preferred establishment sites.
Sciadopitys verticillata — photo of young Japanese Umbrella Pine, taken in a garden in northern California, 1996
Photo by Ethan Johnson
Sciadopitys verticillata — although this conifer is not a pine the close-up of foliage shows the pine-like needles of the Japanese Umbrella Pine.
Photo by Dennis Lee
Sciadopitys verticillata — a large specimen.
Photo by David Marsh
Sciadopitys verticillata — a closeup of foliage detail.
Photo by Iseli Nursery, Inc.
Sciadopitys verticillata — a view of foliage. Photo courtesy of Sandra McLean Cutler, author of "Dwarf & Unusual Conifers Coming of Age.
Photo by Susan Martin
I have probably killed a higher percentage of this species than any other conifer, presumably due to my dry summer air and drip irrigation. I have three new ones (I never learn) and plan to plant them where they will receive overhead water, and more of it. Any other thoughts?
Complete success with any conifer is dependent on trying to replicate the climatic and soil conditions of its native conditions. Southern Japan is very humid and rainy in summer (semi tropical). Give it that and you're virtually guaranteed success. There is also argument that, when young, umbrella pines are very happy hanging out in the under-story, which implies that they'll tolerate quite a bit of shade.
Are you on clay or scree? This species seems to prefer cloud forest conditions on mineral-rich terroir. It's probably that it's rather committed to those conditions.
I'm on clay but I plant on mounds of amended soil with a significant amount of 1/4" lava pebbles added. However, your comment about shade is 'enlightening'. I will site these in spots where they are protected at least during the hottest part of the day. It's odd though, isn't it, that many other Japanese natives do fine here. Maybe they are from northern Japan! Thanks.