Guava trees benefit from well-aerated soil, especially when forming their root systems. The University of Florida recommends digging a hole around a new guava tree, and then loosening the soil to allow for easier root growth.
The guava tree's root system forms a fine, matted network of tendrils. This extensive root system supports the tree against possible uprooting during windy, stormy weather, according to the University of Hawaii at Manoa. Some adult guava trees can withstand the full force of a hurricane.
Guava trees can take root successfully in many different kinds of soil. According to the University of Florida, guava trees bred from cuttings, a common cultivation method, take root no deeper than 18 inches from the surface of the ground. Secondary shoots called root suckers often grow from the roots near the trunk.
Gardeners often use cuttings from guava tree roots to cultivate new trees. Trees cultivated from green wood first receive a solution of indolebutyric acid to encourage good root growth. When applying mulch, gardeners must take care to leave sufficient drainage for the root system to make full use of rainwater.