Today, we are witnessing a phenomenon became commonplace. Most people are gardening only when weather is nice and warm, only when the summertime gives them the want to go to the garden, without considering the needs of plants.
For proper transplantation and good recovery, a tree, whatever, niwaki or not niwaki, does not be installed in the ground in the summer ! About plants, the summer is reserved for aerial development, the winter period is reserved for root development. And root development affects the proper development of the rest of the tree. In addition, in the spring, there is often the wind dries the air and the land, while still low temperatures do not alert us to an imperative need of water. Then in the fall, the rains are more frequent and the soil is still warm. All this is obviously not a coincidence !
For all these reasons, a tree can not be installed in the ground in spring, but in the fall, or so with extreme caution. If you want to install a pre-niwaki or a niwaki in your garden, it is in Autumn !!!