An adjustable wrap-around container system is provided comprising a plurality of connectable modules. Each module includes an outer perimeter wall and an inner perimeter wall defining an outer volume therebetween, the inner perimeter wall surrounding an inner volume that may contain, for example, a post. The inner and outer perimeter walls may both include two segments, joined at an angle, such as 90°, at their inner edges. A module connects to an adjacent module by sliding a tab on the module into a slot in the adjacent module. By adjusting how far each module slides into the adjacent module, the dimensions of the inner volume may be varied. The assembled container can retain solids, such as soil for plants, liquids, or other materials.