Fall Division of Perennials

Fall is an excellent time of year to move and divide many spring and summer blooming perennials. Fall is not a good time to move fall blooming perennials. A good rule of thumb is to divide perennials opposite their season of bloom. By dividing the plant when it is not flowering, all the energy it produces can be directed to root and foliage growth. Fall division should take place from early September to mid-October. Allow at least 4 to 6 weeks before the ground freezes for the plants to become established. Fall divided perennials should be mulched with straw the first winter to prevent heaving caused by alternating freezing and thawing of the soil. The best winter mulch is straw, though bagged leaves are also acceptable. Mulch should be applied when night-time temperatures are consistently in the 20's (mid-November is the usual time frame). A mulch layer 4 or 5 inches thick is usually adequate to protect plants through Iowa's unpredictable winters.

Perennials that can be successfully transplanted and divided in the fall include:

  • yarrow (Achillea spp.)
  • bugle weed (Ajuga reptans)
  • sea pink (Armeria maritima)
  • peachleaf bellflower (Campanula persicifolia)
  • snow-in-summer (Cerastium tomentosum)
  • bleeding heart (Dicentra spectabilis)
  • daylily (Hemerocallis spp.)
  • plantain lily (Hosta spp.)
  • evergreen candytuft (Iberis sempervirens)
  • sundrops (Oenothera spp.)
  • peony (Paeonia lactiflora)
  • oriental poppy (Papaver orientale)
  • garden phlox (Phlox paniculata)
  • Jacobs-ladder (Polemonium caeruleum)
  • blue lungwort (Pulmonaria angustifolia)
  • coneflower (Rudbeckia nitida)
  • false Solomon's seal (Smilacina racemosa)
  • columbine meadow rue (Thalictrum aquilegifolium)
  • Virginia spiderwort (Tradescantia xandersoniana)
  • speedwell (Veronica spp.)

Fall is an excellent time to continue some of the unfinished spring projects in the flower garden. Transplanting many perennials can be just as successful at this time of year as in the spring.

This article originally appeared in the August 23, 1996 issue, p. 147.

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