Which tool is best suited for gardening tasks like trimming shrubs?

Pruning shears are specifically designed for tasks that involve trimming and shaping smaller plants and shrubs, making them the most suitable choice for gardening tasks like trimming shrubs. They are lightweight, easy to handle, and provide the precision needed to make clean cuts on young branches and stems. Their sharp blades can tackle several sizes of branches and are ideal for maintaining the shape and health of the plant by allowing for careful and controlled cuts.

In contrast, a pruning saw is typically used for larger branches and more heavy-duty pruning tasks, while a portable circular saw is designed for cutting through wood and other materials, not for delicate gardening tasks. A portable electric drill is irrelevant in the context of shrub trimming, as it is used for drilling holes rather than cutting or shaping vegetation. Therefore, pruning shears are the most effective tool for the specific task of trimming shrubs.