Cryptomeria

( krip - toe - MEER - ee - uh )

At-A-Glance Information

This genus of large conifers, commonly called Japanese Cedar or Sugi, includes species which need full sun and regular water, and are a fine choice for quick-growing evergreen landscape trees. These trees add 3-4 feet to their height each year, eventually reaching 100 feet tall and 30 feet wide. Bark is reddish brown and foliage is soft bright green to blue-green. Branches are pendulous and covered in overlapping, needle-like leaves. Sometimes, these trees are used to create groves for a Japanese garden effect, but they can also be used as specimens, shade trees, and large-scale screening plants.

cryptomeria Species and Varietals

The genus Cryptomeria includes just one species, Cryptomeria japonica, and is a member of the Cypress family Cupressaceae. Cryptomeria japonica grows well in USDA hardiness zones 5-9 or Sunset growing zones 4-9 and 14-24. To find your zone, click here: Zone Map. Cryptomeria is considered potentially invasive in Hawai'i and South Africa.

'Black Dragon'
Reaches just 4-6 feet tall, with light green new growth that matures to a deep green, and turns almost black in winter temperatures.

'Cristata'
This variety has unusual, twisted growth at branch tips, and reaches 12-15 feet tall and 6-7 feet wide in 10 years, and eventually grows to be about twice that size.

'Elegans'
(Plume Cedar, Plume Cryptomeria)
Foliage is feathery and gray. Winter color is rich copper-red to purple. Slow grower to 20-60 feet tall and 20 feet wide. Variety 'Elegans Aurea' is similar, but turns yellow in wintertime.

'Kitayama'
This variety has a narrow, upright habit to 15-18 feet tall and 8-10 feet wide, with a more compact habit and great winter color.

'Nana'
This variety has an upright habit and reaches 4 feet tall and just as wide. Foliage is dark green.

'Pygmaea' (Dwarf Cryptomeria)
This shrubby dwarf variety reaches 1.5 to 2 fet tall and 2.5 feet wide, with dark green leaves and twisted branches.

'Sekkan-Sugi'
A slow-growing variety with a conical shape that reaches 18-25 feet tall and 12-20 feet wide. New growth is a cream-yellow color.

'Tansu'
Dwarf variety that rarely rises above 15 inches tall and wide.

'Vilmoriniana'
This variety is slow-growing and reaches 1-2 feet tall and wide. Foliage is fluffy and grey, turning bronze in fall and winter. Great as a rock garden or container plant.

'Yoshino'
Similar to the species, except it is smaller, reaching just 30-40 feet tall and 20 feet wide. Foliage is blue-green and turns red in cooler temperatures.

Caring for cryptomeria

These evergreen trees prefer to be grown in full sun, so be sure to choose a spot in the garden that gets at least 6-8 hours of direct sunlight every day. They can grow in partial shade, especially when younger, and will quickly rise above the foliage of other plants, putting on between 3 and 4 feet of growth every year if given adequate irrigation. If planting Cryptomeria as a privacy hedge or windbreak, make sure to give trees enough space to ensure good airflow. This spacing will vary depending on the species grown, but is typically between 8 and 10 feet. Well-draining soil is essential for these trees; they prefer soil to be sandy or loamy in texture, and can adapt to a variety of pH levels but do well with an acidity between 5.0 and 7.0. The importance of good drainage for these trees cannot be understated. Root rot issues are difficult to treat when they take hold.

Newly installed trees will need to be watered regularly to encourage a deep, strong root system. For mature trees, provide water regularly during dry periods of the year; they can typically get by on rainwater alone during the winter months if precipitation is adequate. Apply a layer of mulch around the base of trees after installation is complete; this will help to suppress weed growth, regulate soil temperature around the root zone of the tree, and help to retain moisture. Fertilizing these trees is not necessary; a simple application of an organic compost yearly in springtime should be enough to provide enough nutrients for the active growth period. If soil is particularly poor or if trees seem to be struggling, a springtime application of a slow-release balanced fertilizer may help. Pruning is best completed in late wintertime or early springtime. At the time of pruning, remove damaged, diseased, dead, or crossing branches. Light prunings are recommended; heavy cuts can really stress out trees.

Propagation

Cryptomeria can be propagated either by using cuttings or from seed. To ensure that your propagated plant will have the exact same qualities and characteristics as the parent plant, use the cutting method. If you would like to experiment and see what plant you can grow from seed, just keep in mind that it will not necessarily be the same as the parent plant. To propagate your tree or shrub, follow the instructions below:

Propagating Cryptomeria by Cutting

Gather your materials. You'll need a clean, sanitized, sharp pair of garden shears, rooting hormone, a pencil, and a 3-inch pot filled with well-draining compost or other organic material. A good substrate for propagation of cuttings is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
In late summertime or early fall, choose the plant that you'd like to propagate. Ensure that this plant has had a good watering the night before, as this will improve the chances your cutting will take root. Cut one or more 3-4 inch portion(s) of the end of a side shoot and strip the leaves off of the lower third to half. Make a hole in your planting medium by pushing your pencil into the soil. Dip the end of the stem in rooting hormone, and plant it in your pot. Fill in soil around the cutting to support it, but do not pack it down too much.
Moisten with water, and ensure that the pot has good drainage. Your pot should be kept in warm, sunny conditions indoors (and not in direct sunlight). Water whenever your soil is dry under the top layer. After about eight to ten weeks have passed, your cutting should be rooted. When you notice new growth, you'll know you have roots.
Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring, when you can transplant it to its new home. Ensure that the last frost of the year has occurred before doing this, as it can seriously damage your new shrub.

Propagating Cryptomeria by Seed

Keep in mind that the plant you get from seed will not necessarily mimic all of the characteristics of the parent plant. To propagate by seed, you will need a paper bag, a pot or tray filled with well-draining compost or other organic material, a spray bottle and a fork. The best potting medium for seed germination is a light blend of 1/3 pasteurized soil or compost, 1/3 sand, vermiculite or perlite, and 1/3 coconut coir or peat moss.
Harvest your seeds. The seeds are contained inside of the female cones produced by trees. They are typically mature in fall or winter. Remove cones from the tree, or simply pick them up off of the ground after they have fallen.
Cryptomeria seeds need a period of cold stratification before they can be planted. Place harvested seeds in a damp mixture of sand and potting mix in a sealable container or plastic bag, and place the container in the refrigerator for at least four weeks' time. Remove the seeds from their bed after the cold stratification period, and soak them in lukewarm water for between 12 and 24 hours. Viable seeds will sink, and any that float can be discarded, as they will not germinate.
Water your prepared seed tray or pot filled with soil, and ensure that good drainage is occurring. Place your seeds in your prepared pot or seed tray about a quarter inch to a half-inch under the soil surface. Cover them with soil and water with your spray bottle. Place your tray of seeds in a warm area that receives bright, indirect light. A greenhouse is the most ideal climate, but a planting tray inside a window will do as well. Germination usually takes 7-14 days from sowing. Once you begin to see seedlings sprout and they are able to be handled, transplant them to their own individual 3-inch pots, filled with the same potting medium as described in Step 1. Loosen the seedlings from the potting medium by digging down with the tines of your fork about an inch and a half, gently working the seedling up until it is out. Then, replant the seedling in its individual pot.
Keep the seedling's potting medium moist, but not wet, by spraying the soil with your spray bottle. Keep your new plant in an area with bright light (though not direct sunlight) and temperatures between 55 and 70 degrees Fahrenheit. Ensure that the soil stays moist, but not wet, until the next spring (after the danger of frost has passed), when you can transplant it to its new home.

Cryptomeria seeds are contained inside of the female cones produced by the species in fall and winter.

Cryptomeria seeds are flattened, papery, and reddish-brown.

Problems and Pests

Cryptomeria trees and shrubs are considered potentially invasive in some regions of the world. See species descriptions above for more information. Check with local authorities before planting. Cryptomeria trees can suffer from issues with the following pests and diseases: