Photo of Beverly Sills Iris and article by Joyce Rapp, Goodhue County Master Gardener
There are five basic plant root types. Knowing what kind of root you are dividing makes a more effective division and reduces plant stress.
- Offset roots are found in small plants growing at the base of a larger one. This type includes asters, coneflowers, and hostas.
- Surface roots run on or just below the soil level, as found in Monarda, Sedum and Rudbeckia.
- Long straight tap roots can be divided using a sharp knife to slice down the length of the root. Each piece that has at least one eye, some of the tap root and a few side roots is a viable division. Balloon flower, butterfly weed and oriental poppies are examples here.
- Underground running roots develop suckers as they grow beyond the shade of the mother clump. Suckers can be cut away from the main plant. Japanese anemones and ostrich fern are examples of underground roots.
- Woody roots form when stems rest on the ground and are buried by accumulating mulch. Make a new plant simply by cutting between the rooted stem and mother plant. This root form is found in candytuft and lavender.
Knowing what kind of root system you are dealing with, helps make a more effective division. So enjoy dividing and multiplying your garden!
This is one of three articles on perennials based on information by: Janet Macunovich: Ten Tips on Dividing Perennial Plants http://www.finegardening.com/how-to/articles/dividing-perennials.aspx and Perennials for Minnesota and Wisconsin (Don Engebretson and Willaimson.)