Taiwan cherry (Prunus campanulata) and Japanese cherry (Prunus serrulata) are included in Auckland’s Regional Pest Management Plan and will be banned from further sale from 1 September 2022 https://pestsearch.aucklandcouncil.govt.nz/pest-search/Pruser
The sterile cultivars of Taiwan cherry ‘Mimosa’ and ‘Pink Cloud’ have been specifically exempted from this provision.
NZPPI is putting together a request to exempt six Prunus serrulata cultivars which are also known to be sterile. These are: Prunus ‘Kanzan’, Prunus ‘Mt Fuji’ (synonym ‘Shirotae’), Prunus ‘Shimidsu Sakura’, Prunus ‘Amanogawa’, Prunus ‘Fugenzo’ and Prunus ‘Ichiyo’
Let us know if you propagate and sell other cultivars into the Auckland market. We will do our best to find evidence of their sterility and add them to our exemption request.
We do not believe the actual species Prunus serrulata is even commercially propagated and sold in New Zealand because it does not have the showy floral traits sought after in the bred cultivars. Many of the commercial cultivars are double-flowered and these structural modifications make them sterile. In some of the double flowered cultivars, the stamens have been replaced by an additional row of petals, while in others, it is the pistil which has been modified to form a leaf-like structure. These types of structural modifications to the flower make them sterile so they don’t produce any fruit and can only be propagated by softwood cuttings and grafting on to rootstock.
Interestingly, the species name Prunus serrulata is not a valid classification for many of the bred cultivars which were formed from a series of highly complex inter-specific crosses between different wild cherry species. The Japanese established two terms to differentiate the wild cherries from those of cultivated or garden origin. They were "Yama-zakura" (mountain cherries) for wild plants and "Sato-zakura" (village cherries) for the cultivated selections. They belong to the Cerasus Sato-zakura group, a collective name given to Japanese cherry cultivars of uncertain parentage.
A detailed DNA study found the Cerasus Sato-zakura group were produced by complex inter-specific crosses between Oshima cherry (P. speciosa, endemic to Japan) and wild species such as P. sargentii, P. itosakura, P. levilleana, P. apetala, P. incisa and P. campanulata (Kato, 2021 and Katsuki, 2015). Since the origin of Sato-zakura cherries in Japan is uncertain, Jefferson and Wain (1984) argue that the bred cultivars should not be allied to a species and therefore Prunus serrulata is not a valid classification for these cultivars.
Did you know?
Japanese names for flowering cherries written in kanji (characters) can be pronounced in more than one way, resulting in different written representations. For example, "sekiyama" may appear in English as "sekizan" or "kanzan"; "taguiarashi" can be represented as "ruiran," "ruiarashi," or "taguiran"; and "shirayuki" may be spelled as "shiroyuki," "hakusetsu," "hakuyuki," or "byakusetsu."
References:
Jefferson, R.M. & K.K. Wain. 1984. The nomenclature of cultivated Japanese flowering cherries (Prunus): the Sato-zakura group. US Dept. Agriculture, National Arboretum Contribution No. 5, 44 pp. (archived). https://ia902901.us.archive.org/28/items/nomenclatureofc05jeff/nomenclatureofc05jeff.pdf
Kato (a.) "Origins of Japanese flowering cherry (Prunus subgenus Cerasus) cultivars revealed using nuclear SSR markers". Shuri Kato, Asako Matsumoto, Kensuke Yoshimura, Toshio Katsuki etc. Retrieved February 27, 2021.
(b.) "Origins of Japanese flowering cherry (Prunus subgenus Cerasus) cultivars revealed using nuclear SSR markers". Forestry and Forest Products Research Institute. June 16, 2014. Retrieved February 27, 2021.
Katsuki, Toshio (2015). Sakura. p. 107, In. Wikipedia https://en.wikipedia.org/wiki/Prunus_serrulata