The Fall season is a great time to start splitting and dividing some of the perennials in your garden. This will work for almost all herbaceous perennials that spread in clumps such as black eyed susans, asters, astrantias and countless other varieties.There are a few reasons why you might wish to divide some of your perennials. As the clumps age and develop they begin to tire and the flowers diminish in size, or the clump tends to stress more quickly in the garden because of crowding or reduced nutrient availability.By lifting the plants and dividing them you have the opportunity to add nutrition to the soil and you can chop the plant into several pieces to reduce crowding and promote active and fresh growth. For some perennials and grasses this should be done on a regular 3-5 year cycle, while some perennials like peonies and baptisias are content to remain in place for 20 years.
Another reason to divide a plant is to get more of the parent plant for larger mass plantings or to spread it to another part of the garden (or to give to a friend). Even relatively young plants of a year or two will yield several new plants upon dividing. Many nurseries, including ours use this method to build our plant inventory for sales.
First we gently dig around the clump of perennials that we want to divide and lift the entire clump from the hole. Next I trim the foliage back to give a clear view of the roots and stems.
This also prevents water stress on the new plants because the leaves are not transpiring if they have been removed. With a flat spade I chop the clump into two equal parts and then I chop those parts into two again creating 4 equal sized clumps. At this stage, each clump could be cut into 2 or 3 pieces if more plants are required, as long as there are still a few stems attached to the roots.
Now the new plants can be replanted into the ground in the same location or a new spot of the garden. This is an opportunity to amend the soil to suit the needs of the plant by adding compost for nutrition and moisture retention or sand for better drainage. It is important to plant the divided plants at the same height in the ground as they were before, especially for peonies and irises which won’t flower if planted too deeply.
As our summer droughts become more pronounced it is important to set up new plants for success and one way to do that is to plant and transplant in the fall instead of the spring. Fall is the better season for planting in our area because even though it looks like plants are going dormant, they will continue to put out roots until a hard frost stops them (usually in early December) i would plant anything in fall except for tender plants that would benefit from a summer of growth to help them establish. Any perennials and shrubs that are zone 6 or lower will benefit from a fall planting allowing 9 months to establish and set root before the onset of our dreaded summer drought.
Dividing And Moving Perennials Video above.