Plants in Japanese gardens
Some flower trees are planted. Basicaly, they are showy naturally, some cultivars or double-flower are ocassionaly planted though.
distinctive or showy shrubs are planted.
But they are not principal in Japanese gardens.
Flowers, ferns, bamboos, mosses
Here, I write down other kind of plant, e.g. Bamboo, mosses and ground covers.
Japanese gardening is based on capturing the beauty of nature.
In nature, evergreen trees grow under deciduous trees. Evergreen trees grows gradually. Eventually, forests become evergreen forests. This means deciduous trees finish the life under evergreen trees. This is the nature forest transition in Japan.
Therefore, to follow the above story is the best for planting idea. Of course, in transition, some evergereen trees become taller than deciduous. In the garden, some evergreen trees may taller than deciduous trees.
The aboves are nature picture in Japan.
The bellows are Japanese garden in Japan.
The left picture is temple garden in Kyoto . The right picture is a tea garden.
Both, nature and human created garden have green and nature atmosphire.