When planting a solitary tree or shrub, how much wider should the hole be compared to the root ball?

When planting a solitary tree or shrub, the hole should ideally be two times wider than the root ball. This practice is essential for several reasons.

Firstly, a wider hole allows for better root expansion, which is crucial for the tree or shrub to establish itself successfully in its new environment. When roots encounter the sides of a hole that are too narrow, they can become girdled or restricted, which inhibits growth and can lead to poor health for the plant.

Secondly, providing extra width allows the surrounding soil to be loosened, which encourages root penetration into the undisturbed soil. This improved aeration and drainage are beneficial for root development, as roots can more easily access the nutrients and water needed for the plant's growth.

In contrast, a hole that is only the same width as the root ball does not provide adequate room for roots to spread out, which can lead to a stunted plant. Similarly, a hole that is three times wider or as wide as possible may not necessarily enhance planting success and could lead to other issues such as excessive water retention if the surrounding soil is disturbed. Thus, the recommendation of two times wider strikes a good balance that promotes healthy growth and establishment.