There are various cultivars azalea, many of them are
popular for bonsai. Basically, azalea prefer slightly acidic soil
In Japan soil is usually acidic (pH5.0-7.0), so, it is easy to grow them, however, it maybe difficult to grow it up in some countries.
The below are typical and popular azalea in Japanese garden.
Satsuki azalea Rhododendron indicum (Satsuki)
is the most popular azalea. It blooms around June in Japan whilst
satsuki means May in Japanese. Actually, it blooms the fifth month of
the Asian lunar calendar. Petals are between red and pink.
Japanese version of Wikipedia tell that Satsuki azalea is the most planted tree in Japan. Whilst Wikipedia sometimes tell us incorrect information, I agree with it in this case. I can find Satsuki azalea's blooming everywhere in June Not only Japanese garden, but also roadside trees Satsuki azalea are very beautiful.
Kirishima azalea hododendron * obtusum (Kirishima-tsutsuji)
azalea is native azalea in Kirishima region, Japan. Kirishima is close
to volcano and wild Kirishima azalea lives in severe environment.
Th petals are crimson. When it is in full bloom, trees are covered with red flowers.
Hirado Azalea Rhododendron * pulchrum (Hirado-tsutuji)
Hirado azarea is native in Hirado region, Japan. Leaves are yellowish-green and wooly.
Flower blooms in May. The colour is pink.
Doudan azalea Enkianthus * perulatus
This is deciduous shrubs. Flower is white and small. It is like blue berry. Young leaves are yellowish-green. In autumn, leaves colour change into red. Doudan azalea¬† delight us all season except winter. This is my favourite azalea.
is native to Japan and usually. Most of them in Japanese garden are
shrubs 1 m tall and deciduous.
In Japanese garden, blue or dark purple flowers are match well.
It is said that colour mirrors the pH of the soil, acidic soil make blue flowers and alkaline soils make pink flowers. However, in my experience, the colour became impure when I fed lime (which make the soil alkaline) blue flowers hydrangea.
There are various cultivars camellia. More than 20 kinds of cultivars camellia are planted in the park next my house. Some of them bloom before winter, the else bloom in spring.
White flowering shrubs in Japanese garden
Spiraea cantoniensis (Kodemari)
This is a decidous shrub growing up to 1.5 m. Branches are weeping. Flower is white and 1cm big. they swarm like ball. In japanese language,¬† demari means old Japanese ball. This is the origin of the name.
Spiraea thunbergii (Yukiyanagi)
This deciduous blooms in the begining of April. Many small (1 cm)
white¬† flowers decorate weeping branches.
This is a very strong tree. Although I trimmed many times,¬† branch leaf¬† bud against my will.
Yellow flowering shrubs in Japanese garden
Japanese kerria (Yamabuki)
This is a decidous weeping shrub. The flower blooms in April. A flower has five petals whilst double-flowered is sometimes planted. Petal is light yellow. It is strong shrub and grows. Sunshine is not always neccessary .
This is a decidous weeping shrub. Petal is yellow with a deeply four-lobed corolla. In full blooming, it is very showy, all branches are filled with yellow. It is tough and lives in severe environment.