Landscape

LANDSCAPE Divide and Multiply

By Pat Raven, Ph.D., with Julie Hess

Autumn is a wonderful time to work in your garden. The heat from summer is gone, and the drier, resort weather days the metro area is known for have arrived. It is the perfect time to divide perennials to reinvigorate them and to multiply their numbers.

Why divide? When a plant outgrows its allocated space, it starts to have dead space in the middle, it suffers from reduced bloom due to selfcompetition, or you just want to make more starts to fill out your border or share with friends.

When to divide? Autumn divisions should be made about a month before first frost, plants blooming now get split in the very early spring, and a few fleshy rhizomatous plants like irises should receive attention in midsummer.

What to divide now? Daffodils, daylilies, bellflowers, lungwort, coreopsis, peonies, oriental poppies, Shasta daisies, sedums and yarrow, to name a few, should be split now. Wait till spring to divide fall bloomers like garden mums, coneflowers and coral bells. Summer-dormant plants, such as bleeding heart, lycoris and irises, may be split as soon as the foliage dries off. Some perennials really resent being disturbed, including many woody plants like Russian sage, santolina, butterfly weed, and false indigo. Japanese anemones, also in this group, often have babies on the edges that may be taken without upsetting the main clump.

How to prepare. Choose a time to work with few interruptions. It is best, in most cases, to get the clump divided and replanted before it dries out. Wait for a good soaking rain, or water well a day before to make soil softer to work and cause less root damage during extraction. A prediction of showers to come is also a great forecast, as overcast and damp days help new plants reestablish more successfully.

Use a garden canvas or tarpaulin as your workspace to collect loose soil easily and make cleanup a breeze. Work in the shade when possible. A portable patio umbrella is handy for this purpose.

Start digging. Prepare the new planting holes first. If you plan to replant only in the original location, posh up the pit with fresh compost and a very light dressing of fertilizer.

My tool of choice for dividing clumps is the Radius Ergonomic Stainless-Steel Fork (digging fork 43 inches, border fork 41 inches). With a distinctive round, green handle, it was designed to minimize wrist exertion. The tines are slender and smooth, requiring less effort to push into clay soils or tight root balls. For folks with back issues, a long-handled (48-inch) spading fork may be easier to use. One makes a great gift for older gardeners.

Dig around the plant 4 or 5 inches out to loosen it, and then lift the entire clump onto the tarp with a spading fork. Divide the plant with a garden saw, spade or sharp knife. Choose your pieces for replanting, put them back in the ground ½ inch higher than they were (to account for soil settling) and water in well. If segments are very leafy, remove up to half of the foliage to help the damaged roots recover more quickly.

Wrap the remaining pass-around plants in damp newspaper. Share them as quickly as possible with friends or neighbors so that they have the best chance of survival. Finally, pat yourself on the back for a job well done! ln