Family

Cupressaceae

Common name/s ?

Granny’s ringlets, Japanese red cedar, sugi.

Skill rating

Easy

Origin

Japan and China.

Type of plant ?

Evergreen, perennial conifer shrub or tree.

Hardiness zone ?

RHS zone

Hardy

EGF zone

H4

USDA zone

6-9

Eventual size

Up to 6m in height and 2.5m spread. Size does seem to vary quite a bit between different examples of this conifer.

Growth rate ?

Very slow growing, will reach full height in around 20 years.

Shape it grows into

There appear to be two different variations to this cultivar – one growing into a conical shaped tree, the other remaining more bush like and irregular in shape.

Season/s of interest

Year round.

Where to grow it

Happy in full sun or part shade.
Prefers well drained to moist soil.

Prefers a sheltered location. Happy on all soil types.

Cryptomeria japonica 'Spiralis'

Features

Foliage remains bright green throughout the year. The leaves twist around the stems, hence its name.

What to use it for

In a conifer bed or as an architectural feature (particularly for the distinctive twisted leaves).

How to look after it

Requires little maintenance.

How to prune it

You shouldn’t find that much pruning is required for this plant. Remove any dead, diseased or damaged growth in autumn or midwinter as necessary.

Unlike many conifers, Cryptomeria will grow from old wood, so it can be cut back hard or coppiced if required.

How to propagate it

Semi-ripe cuttings can be taken from late summer to early autumn and should root readily.

Seeds, which may not come true from this cultivar, can be collected from female cones as they ripen (which will take a year) and brown in autumn. Store them dry then stratify in damp peat in the fridge for 3 weeks before sowing with bottom heat of 15-20˚C.

If the plant is too small to yield sufficient material for cutting, and if you have the skills to do so, it can be grafted with a spliced side-veneer graft onto pot-grown rootstocks. Keep the graft at 20˚C for a few weeks until the callus forms.

Common problems

Generally free of pests and diseases.

Other useful information

Cryptomeria is the national tree of Japan and can be found at many sacred sites in Japan.