Cryptomeria japonica (common name Japanese Cedar) is not a conifer that like our weather at all. Unless you really really like them, don’t bother to grow them here. If you do grow them, be mentally prepared that they can leave any winter.
Cryptomeria japonica ‘Knaptenensis’
One of the most beautiful conifers I have. The white foliage is most striking in August. It has remained small after many years. It suffered winter damage easily for many years until I moved it to a more sheltered spot a few years ago. However, its white foliage appears to be not disappearing in shady condition.
Cryptomeria japonica ‘Sekkan’
This plant came to me labelled as Cryptomeria japonica ‘Sekkan Sugi’. RHS Encyclopedia of Conifers indicated that this name is syn. for Cryptomeria japonica ‘Cristata’. However, this plant does not show the characteristics of ‘Cristata’. It looks more like Cryptomeria japonica ‘Sekkan’, and my understanding is ‘sugi’ is a Japanese word for cryptomeria. Therefore, I tentatively labelled my plant Cryptomeria japonica ‘Sekkan’.