a root watering system for a tree or a shrub includes an outer container of a water - permeable , flexible material . a perforated , hollow inner support structure maintains the flexible material in an elongated shape between first and second ends . the outer container is positioned in the ground with the elongated shape proximate to the roots of the tree or shrub and with the first end proximate to the surface of the ground and with the second end near a lower end extending generally downward toward the lower portion of the root system of the tree or shrub . water applied to the ground proximate the upper end of the outer container enters the first end and fills the outer container including the hollow inner support structure . water within the outer container is released through the porous , flexible material to provide water to the root system of the tree or shrub .