Cryptomeria japonica 'Knaptonensis' / Japanese cedar of Knapton

Cryptomeria japonica 'Knaptonensis' is a slow-growing, irregularly globose selection of Japanese cedar with densely packed light-green foliage splashed with bright white variegation. After 10 years of growth, a mature specimen will measure 12 to 18 inches (20 - 30 cm) tall and wide, a rate of growth of a bit over 1 inch (3 cm).

This cultivar should never be planted somewhere where it receives direct afternoon sun, as the white variegation burns very easily. 'Knaptonensis' is at its best when planted in a northern or eastern exposure under dappled shade where it receives only bright morning light. In this situation the white variegation is very strong and will not burn. However, if planted in deep shade, the variegation will be quite muted; the plant will appear to be mostly green.

This cultivar originated as a witch's broom found in 1930 on a specimen of Cryptomeria japonica 'Nana Albospica' by Murray Hornibrook on Madre Island in Lago Maggiore, Italy. Occasionally, 'Knaptonensis' will develop long, coarse shoots of new growth (reversions back to 'Nana Albospica'). The gardener should remove these when discovered. A light shearing on a yearly basis will keep the plant tight and more attractive. The cultivar name refers to Knapton, an English village in Norfolk county, United Kingdom.

Cryptomeria japonica 'Knaptonensis' Photographed in a woodland setting at The US National Arboretum's Asian Collection in Washington, D.C. during May 2006.
Photo by Dax Herbst
Cryptomeria japonica 'Knaptonensis' Photo copyright of The Wildlife & Conifer Garden Donated by Don and Nonda Surrat, Ohio, USA.
Photo by Nonda Surratt
Photographed in Will Fletcher's Hobbiton Gardens, Port Orchard, WA, during the Western Regional Meeting, 2013.
Photo by Sean Callahan


Karen Hartman

Bought a small pot in 2016. Planted in an outdoor planter. Kept in greenhouse every winter (in Eugene, OR). Transplanted this spring into a larger pot and it lives in sheltered area/semi-shade on back deck. All of the sudden, the lower branches are turning brown and dying and moving up the plant. It gets a good watering every other day. What gives?

Maxwell Cohn

The root system is probably failing. Does the pot have drainage? What did you use for potting medium? Do you plant too deep? Can you see the root flare?

Watering every other day might be too much. Is the soil fairly dry before watering?