| Family | Hydrangeaceae |
| Scientific name | Hydrangea macrophylla (Thunberg) Seringe var. megacarpa Ohwi |
| Synonyms | Hydrangea macrophylla (Thunberg) Seringe subsp. yezoensis (Koidzumi) Kitamura; Hydrangea serrata (Thunberg ex Murray) Seringe var. megacarpa (Ohwi) H. Ohba |
| Common name | (Japanese common name) ezo-ajisai [ezo hydrangea (ezo = an old name of Hokkaido)] |
| (English common name) none | |
| Distribution | (Japan) Hokkaido, Honshu (Japan Sea side) |
| (Other nations) none | |
| Chromosomal number | 2n=36 |
| Description | Plants 1-1.5m. Leaves 10-17cm. Flowers white, pale red, purple or blue, flowering in June to August. Deciduous. Shrub. |
| June 2007 at Tsukuba Botanical Garden |
June 2007 at Tsukuba Botanical Garden |
| June 2007 at Tsukuba Botanical Garden |
June 2007 at Tsukuba Botanical Garden |
| June 2007 at Tsukuba Botanical Garden |