つつじ, さつき, あざれあ【躑躅, 皐月, アザレア】
■ ツツジ (躑躅) ツツジ is the type of rhododendron commonly referred to as "azalea" in English. Although azalea is no longer recognized as a distinct genus, gardeners often make a distinction between azaleas and rhododendrons, and this is also the case in Japan, where シャクナゲ (石楠花, rhododendrons) and ツツジ (躑躅, azaleas) are treated as separate groups of plants.
The name ツツジ covers many native species. Although the term "Japanese azaleas" in the English-speaking world usually refers to evergreen species and their hybrids only, some of the plants considered to be a type of ツツジ in Japan are deciduous. The following are some of the species that are referred to as ツツジ.
レンゲツツジ (蓮華躑躅, Rhododendron japonicum)
ヤマツツジ (山躑躅, Rhododendron kaempferi)
キリシマツツジ/クルメツツジ (霧島躑躅/久留米躑躅, Rhododendron obtusum and its hybrids)
ミヤマキリシマ (深山霧島, Rhododendron kiusianum)
ウンゼンツツジ (雲仙躑躅, Rhododendron serpyllifolium)
■ サツキ (皐月) サツキ, Rhododendron indicum, is strictly a type of ツツジ, but in Japan it is often treated as a separate group of plants, as evident from many references to 「ツツジやサツキ」, as in the examples below. The name サツキ comes from the old name for the month of May, indicating the time of flower. This is by the old, lunar calendar, and サツキ actually flowers in late May to early June, when ツツジ has finished flowering. サツキ has been bred extensively for centuries in Japan, and there are hundreds of named varieties with a huge range of flower colours, shapes and markings.
It is sometimes stated that サツキ was bred from a wild species of Rhododendron called 岩ツツジ, but this is rather misleading. The plant known in the botanical world as イワツツジ is not a rhododendron at all but Vaccinium praestans or Kamchatka bilberry. There are several species of wild azaleas that are commonly called 岩ツツジ because of their natural habitat, such as ミツバツツジ (三葉躑躅, Rhododendron dilatatum) and レンゲツツジ.
(Kyoto Shimbun 2000.4.28 News)
In the broad sense, アザレア is the "fashionable" name for any ツツジ, including サツキ.
In the narrow sense, アザレア is another name for 西洋ツツジ and refers specifically to Belgian pot azaleas (also called Belgian Indian hybrids). They are tender azaleas with showy flowers for indoor culture developed in Belgium from Southern Indian (or Indica) azaleas, a group of large-flowered hybrids resulting mainly from Rhododendron indicum (サツキ) and Rhododendron simsii (タイワンヤマツツジ) crosses.
This entry was created by Yuno Hanlon.