PLANTS FOR JAPANESE GARDENS
If you have a pond in your Japanese style garden, you've got to have a water lily. They provide shade for fish in the summer and help to filtrate your pond. Once planted, they don't need much care but most varieties will need six to eight hours of sunlight each day. Remove yellow leaves from the plant so that they don't spoil the water. Some varieties of Water Lily can be grown in a container so you don't always need a pond.
If you can provide good shelter then you've got to have an acer or two. In an exposed location, the leaves will tend to get shredded but you really can't beat them for leaf colour and shape. Because they are slow growing, Acers can be expensive but you pay for the time the nursery puts in to growing it and it's well worth it.
No Japanese garden would be complete without a bamboo. Plant your bamboo in a sunny spot and water frequently after planting. Yellowing of the leaves, followed by leaf drop in spring is normal since bamboos renew their leaves in the spring. Keep your bamboo well watered until it reaches its desired size. After that, you can relax a little but pay it special attention during periods of drought.