Fall is for planting…and transplanting. It’s the ideal season to rein in overgrown perennials by splitting them and sharing them with friends.When perennials overtake your garden, dig up the plants and divide the roots into four pieces. Then replant one piece back into your garden and place the others in nursery pots to give to your gardening friends, plant in another of your gardens, or donate to a garden club plant sale.When digging, dig up the whole plant. To divide the plant, lay it on the ground and split the root in half. Then cut each half in half. In other words, quarter the plant. Different size roots will require different tools to split the roots apart. Whatever tool you use, be sure it is sharp enough to make clean cuts. A plant with thin, tender roots may be cut with a trowel or pruning shears. Bigger, thicker roots may need a shovel or axe, while the really obstinate roots may need loppers or a pruning saw to cut them apart.When replanting, the planting technique you use for nursery stock applies. Chances are the hole from which you just dug the plant is the right size. If you are the recipient of a split perennial, however, you will be digging a new hole. Dig the hole at least twice the diameter of the root, but no deeper. Hold the plant upright in the hole as you backfill up to the previous soil line. Tamp lightly to remove any air pockets and give it a good drink of water.Sharing split perennials is a good way to expand and diversify your perennial beds without spending a cent. Getting a group of friends together over a cup of coffee or iced tea and making the plant exchange a social event can be very enjoyable as well as beneficial for all participants.