How to divide plants. Dividing plants is easy. Simply dig up the entire clump and then carefully divide the crown and root ball into two or more section, depending on the size of the clump. Sometimes you can divide garden plants with your hands, as with many bulb species, while the use of a sharp knife or garden spade is oftentimes necessary to get the job done when dividing plants. Once you have divided plants, shake off the excess soil and remove any dead growth. You might want to cut the plan