Dividing Perennials in the Fall

With fall ‘officially’ here, questions have been coming in concerning dividing perennials. As a sweeping generalization, they should be divided in the season opposite their flowering time. This means spring flowering plants should be divided in the fall and fall bearing plants in the spring. Many summer blooming plants can be divided in either the fall or spring. This allows for maximum energy utilization for foliage and root production, with the result being healthier and showier flowers the following season.

Here is a short list of some herbaceous perennials that can be divided at this time of year:

Achillea x ‘Coronation Gold’ – now or in the early spring

Ajuga reptans

Cersastium tomentosum

Dicentra spectabilis

Hemerocallis species

Hosta species

Paeonia lactiflora

Phlox paniculata

Of course, if the need arises to move or divide any herbaceous perennial, then do it irregardless of the season of bloom. Gardeners would rather attempt to save a favorite plant than to know doing nothing will spell its doom.

- Ron Smith, NDSU Horticulturist and Turfgrass Specialist, ISA Certified Arborist

(Pictured: "Hosta", Ian BC North,available under a Creative Commons Attribution-NonCommericial 2.0 license)