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(First upload on May 28 2011. Last on April 5 2019) [ 日本語 | English ]

Rhododendron spp. for gardening






Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

Rhododendron L. Iツツジ)

Used for gardening
R. erubescens Hutch. (ベニオトメシャクナゲ*)
R. indicum (L.) Sweet (サツキ)

cv. hakatajiro (ハカタジロ)

R. molle (Blume) G. Don (トウレンゲツツジ)

f. flavum (Miyoshi) Yonek. (キレンゲツツジ)

R. schlippenbachii Maxim. (クロフネツツジ)
R. × mucronatum (Blume) G. Don (リュウキュウツツジ)

cv. kanoko (カノコ)
cv. narcissiflorum (シロマンヨウ)
cv. plenum (フジマンヨウ)

R. × pulchrum Sweet (ヒラドツツジ)

cv oomurasaki (オオムラサキツツジ)

索引

Rhododendron erubescens transplanted at SEATAC Airport


Etymology of species epithet
Beni-otome-shakunage* (ベニオトメシャクナゲ, 紅乙女石楠花) (*: tentative translation), Pere Farges rhododendron
Life form: evergreen shrub < 3 m high
Origin: Sichuan, Gansu, and Hubei in China (unpopular gardening tree in Japan)
Habitat: acid soil
Synonyms:

Rhododendron oreodoxa var. Franch. var. fargesii (Franch.) D. F. Chamb.
Rhododendron fargesii Franch.

ST1 ST2 ST3
[1-3] at SEATAC International Airport, WA, on March 23 2013.

Rhododendron indicum in Japan


Satsuki (サツキ, 皐月), satsuki azalea
Life form: (semi-)evergreen shrub
Distribution: south to Kanto District, Japan (endemic)
Habitat: moistened, acidic soils and rocks in valleys
Shoot: dense hair when young
Leaf: producing spring and summer leaves, sharp top
Stamen: five
Use: gardening (≈ 2,000 cultivars), hedge, bonsai, etc. (transplanted in Hokkaido)
Chromosome number: 2n = 26
f. otakumi T. Yamaz. (オタクミツツジ)
Cultivars (probably more than 1,000): Hakatajiro (ハカタジロ, dwarf stem and white flower), etc.

ST1 ST2 ST3
[1-3] at Kanda, Tokyo, on May 11 2013. At that day, it was a festival. (平成二十五年 五月十二日(日曜) 神田明神氏子神輿入り)
ST3 ST3 ST3
[4-6] on the southwestern slope of Mount Koma (flora), southern Hokkaido, on July 10 2017. This species is not naturally distributed in Hokkaido. Probably immigrated by wind from the bottom of the mountain.

cv. Hakatajiro

ST1 ST2
[1/2] besides Patagonia, N13/W4, North Ward, Sapporo, on June 20 2018.

Rhododendron schlippenbachii Maxim. transplanted in Sapporo


Kurofunetsutsuji (クロフネツツジ, 黒船躑躅), royal azalea
Life form: deciduous shrub < 5 m tall
Distribution: Manchuria - Far East - Korea (introduced to Japan in 1668)
Habitat: mountainous forests
Flower: red-brown spots on three upper petals

ST1 ST2 ST3
ST4 ST5 ST6
[1-3] this shrub was transplanted on September 26 1980 for the golden anniversary of Faculty of Science, Hokkaido University. In front of the Hokkaido University Museum on May 20 2011. This year I entered the university. [4-6] at a house garden, N20/W4, North Ward, Sapporo, on May 17 2017.

Rhododendron × mucronatum (Blume) G. Don in Hokkaido


Ryukyutsutsuji (リュウキュウツツジ, 琉球躑躅)
Lifie form: semi-evergreen shrub
Distribution: cultivated after Edo Era
Leaf: hairy, producint spring and summer leaves

ST1 ST2 ST3
[1-3] in front of a building, N15/E1, East Ward, Sapporo, on June 1 2018.

Rhododendron × pulchrum Sweet in Japan


Hiradotsutsuji (ヒラドツツジ, 平戸躑躅), snow azalea or Hirado azalea
Life form: evergreen shrub < 3 m high
Distribution: transplanted (in various regions of Japan), recorded in "Wakansansaizue (和漢三才図会 1712)
Habitat: partial sun to partial shade on well-drained, acidic or neutral soil

Tolerant to air pollution - street tree

Cultivars: > 300 spp.
cv oomurasaki
Oomurasakitsutsuji (オオムラサキツツジ, 大紫躑躅), pretty azalea, pretty rhododendron, purple Aaalea, etc.
Synonyms:

Rhododendron oomurasaki Makino
Rhododendron × pulchrum Sweet var. speciosum (Makino) H. Hara

Hybrid: R. indicum (L.) Sweet (サツキ) × R. mucronatum G. Don (キシツツジ), cultived after the Edo Era
cv shounoshin (ショウノシン, 正之進). pink flower → pale pink
cv shirotae (シロタエ, 白妙). white flower
cv akebono (アケボノ, 曙), pink flower
cv oomurasaki

ST1 ST2 ST3
ST4
[1-3] at Kansai International Airport on March 27 2013. [4] on the a historical place of Kitano purification plant, Kobe, western Japan, on March 16 2019.

cv shirotae

ST1 ST2 ST3
[1-3] in a small garden near N17/E1, East Ward, Sapporo, on June 1 2018.

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