Written by davethetreecenters • August 15 Everything you need to know about Japanese Cedar – Cryptomeria
Evergreens are among the most important plants in any garden. They bring a look of permanence and structure, with forms that are with us every day of the year. The garden will still change around them, but their presence brings calm and form in ways that no other plants can. At first glance they may all look the same, but the more you look the more you see, and their diversity becomes a source of endless beauty and interest. Some, like pines or firs, come in many different species, but Japanese Cedar is a ‘plant unto itself’, because there is just one, which botanists call Cryptomeria japonica. However there are around 80 different forms of this plant, from giant forest trees to tiny miniatures, so from that one species there is much diversity and garden value.
Cryptomeria is called a cedar because it has some of the characteristics of ‘true’ cedar (Cedrus) – evergreen, aromatic foliage – but this is a catch-all name, and it’s important to always add ‘Japanese’ when you call it a cedar, to avoid confusion. For some more on the various plants all called cedar, check out this earlier blog post.
As you might guess, Cryptomeria does indeed come from Japan, where it is called Sugi (杉).
There is debate over exactly where it originally grew wild there, since it has been planted in extensive forests for over 1,000 years, becoming part of the ‘natural’ vegetation of the country. One place where it definitely does grow wild is on the UNESCO World Heritage island of Yakushima, in southern Japan – a magical place of ancient forests and wildlife. Elsewhere it is hard to distinguish natural forest from planted ones.
In Japan Sugi is a major and important lumber tree, with forest giants growing over 200 feet tall, with trunks 12 feet across. The wood is aromatic, pinkish, lightweight but strong, and waterproof, making it resistant to decay. It is used extensively for all kinds of construction and paneling in Japan, and has grown in popularity in other countries, particularly on the islands of the Azores, in India and in New Zealand, where it grows well.
There are extensive forests of Japanese cedar in China, too. These are also ancient, and there has long been dispute about whether this tree is native there. Because of its long history of being planted, there are distinct local varieties in Japan, but none of the trees in China have been shown to be outside the range of those varieties, so although Chinese trees are describes as ‘var. sinensis’, it is unlikely they are truly native. Trade in plants between China and Japan has an extensive and long history.
Growing Japanese Cedar
Although wild trees are only rarely planted in gardens, since they grow so large, there are many smaller varieties that are popular garden favorites. As a group their soft, often fuzzy foliage has lots of charm, combined with their lighter green coloring and unique shapes. Sadly, Japanese Cedar is not a tree for every garden in America. It grows best in climates that are fairly mild in winter – no colder than zone 6 – and moist, as this is a tree that enjoys deep soil and abundant water. That still leaves much of the northeast and of course the northwest. In hotter, drier places these limitations can partly be overcome by good soil preparation, mulch and watering, and by choosing a sheltered spot protected from winter winds and hot, dry, afternoon sun. So don’t immediately dismiss this tree if your climate is not ideal.
Features of Japanese Cedar
There are good reasons to grow taller Cryptomeria varieties in your garden, if you have room. The long, straight trunk is graceful, and the bark is especially beautiful, a gorgeous reddish-brown, peeling in long, narrow strips. When your dwarf varieties grow taller, it is great to open them up to expose the trunk where you can – it will add to the beauty of the tree, and it’s very appropriate if you are growing them in a Japanese-themed garden, where they are right at home.
Like many evergreens, the leaves of Japanese Cedar are of two kinds. On young plants they are up to ½ inch long, slender and pointed. These ‘juvenile’ leaves are replaced within a year on seedlings with ‘adult’ leaves. Those are shorter, thicker, and angled closer to the stems. See the picture to grasp the difference, and notice also the young cones, which are round and ¾ of an inch across when mature.
The Best Varieties to Grow
We can divide the varieties of Japanese cedar – there are about 80 in total – into two main groups. There are those that cater to our love of the full-sized tree, being taller varieties that show the beautiful trunks and bark, and are tree-like, but more compact. The others are mostly rounded domes of various sizes, great for foundation planting, rock gardens and pots.
Let’s start with the upright types:
‘Yoshino’ – this variety came to America from Japan in the 1920s, and it is a compact version of the natural tree – perfect for garden planting. It’s a great substitute for the Leyland Cypress (which has ‘issues’ in some areas for growing so large), and more tolerant of light shade than that tree. It grows up to 18 inches a year – a great speed if you want quick hedges or screening – and within 10 years it will pass 10 feet tall and 6 feet wide, developing into a beautiful pyramidal tree if left untrimmed. The foliage is a vibrant lime-green in spring, gradually darkening until by winter it is dark green with plum-purple overtones. A wonderful tree that remains neat and handsome without any trimming. Highly recommended.
‘Gyokuryu’ – often called the Magic Dragon Cryptomeria, this is another fast-grower, adding 18 inches a year and ultimately reaching 30 feet in height. If you don’t like the plum or reddish colors of a Japanese cedar in winter, then plant this one, because it normally stays green throughout the cold months.
‘Spiralis’ – a unique small upright tree, with horizontal branches and slightly pendulous tips, the needles have a pronounced spiraling around the stems and a twist, making the young stems look more rope-like. When young it will be a rounded bush, but as it grows it discovers its direction, and rises to be more tree like. Mature trees can be 20 feet tall and 10 feet wide.
‘Elegans’ – although not so widely grown anymore, this is a great plant for displaying very juvenile, fluffy foliage on an upright tree. It was an early introduction from Japan, in the 1860s, and it was the main form grown for many decades. It can reach 10 feet in as many years, and has strong purple-red winter foliage. Prone to collapsing, it needs pruning to keep its upright form, which is why it is not seen so much anymore. There is a dwarf form called ‘Elegans Nana’
Now let’s look at some mounding varieties:
‘Tenzan’ – at the opposite end of the scale, this variety is the smallest of all Japanese cedars, growing to about 6 inches high and 8 inches wide in 10 years. Of course it needs some special care, and probably only grows in zone 7, but what a gem it is. Grow it in an attractive pot, perhaps treating it like a bonsai, and capture the beauty of this tree in miniature. You don’t even need a garden – an east-facing window sill will be just fine, with perhaps some extra care in winter.
‘Mushroom’ – if you like the mounded look of ‘Tenzan’, but it’s too small for you, this variety is the answer. Forming a mound of soft, juvenile foliage, it adds 2 or 3 inches a year to be 2 feet tall and 3 feet wide within 10 years. It’s perfect nestling between rocks on a slope, or cuddling up to the bottom step of the flight that leads to your front door. It is also known for the gorgeous plum colored winter foliage, making this a 2-season beauty.
‘Globosa Nana’ – usually known as the Dwarf Globe Japanese Cedar, this is one of those plants that tricks the unwary. “Oh, it’s so cute!” is the response when you see a young one, but don’t tuck it into a small space, because within 10 years it will be 5 or 6 feet tall and wide, making an elegant mound of slightly-pendulous branches. It will continue to become larger, so don’t crowd it – just enjoy it.
‘Compressa’ – this is another great miniature form, taking 10 years to reach 15 or 18 inches tall and wide, often becoming egg-shaped, and one day being 3 feet tall. Reddish-brown in winter, it perfect for both the garden and for pots – growing dwarf evergreens in pots is a great hobby, especially if you only have a small garden.