Woody > Cryptomeria > Cryptomeria japonica > Cryptomeria japonica 'Knaptonensis'
Cryptomeria japonica
'Knaptonensis'
Origin: Japan.
Mike's
Opinion
"
This Dwarf Shrub is an eye catching attraction in the garden. It was cultivated by Murray Hornibrook in Italy in 1930 off a witches broom of C. japonica ‘Nana Albospica’. The cultivar was named after the town of Knapton village in Norfolk county of the United Kingdom. Its flashy new growth contrasts perfectly with the light green foliage, and its dwarf form make this plant very versatile in the garden. Its size also aides in finding a wind protected location.
Michael Pascoe, NDP., ODH., CLT., MSc. (Plant Conservation)
"
| Family |
| Cupressaceae |
| Genus |
| Cryptomeria |
| Species |
| japonica |
| Cultivar |
| 'Knaptonensis' |
| Category |
| Woody |
| Type |
| Shrub (evergreen) |
| USDA Hardiness Zone |
| 5 - 8 |
| Canadian Hardiness Zone |
| 4a - 8a |
| RHS Hardiness Zone |
| H4 - H7 |
| Temperature (°C) |
| (-29) - (-7) |
| Temperature (°F) |
| (-20) - 20 |
| Height |
| 1.83 m |
| Spread |
| 0.91 m |
Photographs
Description and Growing Information
Flowering Period
| General Description |
| This dwarf conifer shrub displays a pyramidal or conical shape. The growth is very uniform and is quite dense. It is very slow growing and displays a soft silver-white colour in its new growth that contrast nicely with the older light green foliage. |
| Landscape |
| This cultivar can be used in the landscape as a specimen or accent plant. Typically for the best possible placement in the garden, wind protection should be taken into consideration with this plant. This shrub also does well in partial shade, this will give you a variety of potential locations. |
| Cultivation |
| This shrub prefers rich deep soils that are light and permeable. The soil should be slightly acidic and be able to retain moisture. A protected location in full sun is ideal, but it can handle partial shade. This plant grows in both warm and cold seasons; the warm seasons see 2.5 to 3.5 cm of growth while the colder season only see 0.9 to 2 cm. |
| Shape |
| This plant has a round globular shape in its early life. When it becomes more mature, this dwarf shrub stretches up a main leader and creates a uniform conical/pyramidal shape. There is usually very little space between the ground and the skirt of the tree. |
| Growth |
| Slow |
| ID Characteristic |
| The silvery-white new growth is the most attractive feature of this plant. If this plant is kept in a warmer climate and does not experience a cold period you will not only loose the variegated colour of the new growth, you will also have this cultivar revert its growth habits to be more similar to its parent plant C. japonica ‘Nana Albospica’. This results in losing the uniformity. |
| Pests |
| Leaf blight/leaf spot occurs on this plant, along with red spider mites and maskell scale. |
| Habitat |
| Horticultural origin. |
| Bark/Stem Description |
| The stems are light green, and they droop and spread. The stems primary shoots are 6 to 20 cm and the secondary shoots are 9 to 12 cm. On occasion this shrub has been known to develop long course shoots of new growth. The bark is a reddish brown that slowly peels off in long strips, giving it some aesthetic value in its old age. |
| Flower/Leaf Bud Description |
| Small inconspicuous buds, it is not very noticeable or noteworthy. |
| Leaf Description |
| The light green awl like foliage is slightly incurved with needles that are 2 to 4 mm in length. Growth in the cooler season will have stunted needles that are 1 to 3 mm long. The first foliage of the year is shorter than the foliage that comes after. |
| Flower Description |
| The monoecious flower is not noticeable and displays an unappealing dry brown colour that is easily ignored. |
| Fruit Description |
| Cone production is quite a rare site for this cultivar. The cones would occur at the terminal of the stems and are evenly rounded in shape, about 1 inch in size. The colour is dark brown and it takes half a year for the cones to mature. |
| Colour Description |
| This shrub has quite the palette of colours, like the light green foliage and the soft silvery-white new growth. If not protected from the wind, the plant will display an appealing brown colour. Although the dense foliage hides the reddish-brown bark, it becomes more visible as the plant matures. |
| Texture Description |
| The awl-like needles are firm and stiff with blunt ends. The texture is medium-like, since the needles are not sharp but do have a strong structure. |
| Propagation |
| For this cultivar, male and female strobili are a rarity, so taking semi-hardwood cuttings in the latter half of summer is the common practice when it comes to propagating this plant. |
| Ethnobotanical Uses (Disclaimer) |
| The original species has been used for forest restoration in Japan since the 17th century. |
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