Do the Math
Perennial Division
By Ann Hutchins |
| Name |
How Often and When |
Method |
- Aster
(Aster)
|
- Every year or two in spring
|
- Spreading root division, replanting younger outer pieces
|
- Bearded Iris
(Iris)
|
- Every 3 to 4 years as plants become crowded, 1 month after flowering to September
|
- Rhizome division
-
|
- Bellflower
(Campanula)
|
- Every 2-3 years or as it gets crowded, spring
|
Spreading root division |
- Black-eyed Susan (Rudbeckia)
|
Every 3-4 years, early spring or fall |
- Spreading root division
|
- Bleeding Heart
(Dicentra)
|
- Rarely, early spring
|
- Clump root system; be gentle with brittle roots; cut with sharp knife
|
- Coneflower
(Echincea)
|
- 4-5 years, spring or early fall
|
- Spreading root system but can be left alone for many years; use sharp knife
|
- Coral Bells
(Heuchera)
|
- 1 to 3 years in spring
|
- Cut crown apart; discard old woody, center
|
- Clematis
(Clematis)
|
- 10 years or more
|
- Divide only some species; cut crown with knife or spade
|
- Cranesbill
(Geranium)
|
- Every 2-4 years, early spring or fall
|
- Spreading root division, most can be pulled apart by hand
|
- Daylily
(Hemerocallis)
|
- Every 3 to 6 years, or as needed to increase numbers, spring, summer, or fall; best after blooming
|
- Divide roots into segments; divisions with three or more shoots will bloom sooner; division promotes heavier blooming
|
- Gayfeather
(Liatris)
|
- 3 to 5 years in spring
|
- Cut into sections with sharp knife
|
- Garden Phlox
(Phlox)
|
- Every 3-4 years, early spring or fall
|
- Spreading root system
|
- Hosta
(Hosta)
|
- 6 to 10 years, spring or fall; looks best if not divided often
|
- Clump root system; divide into clumps with one to three eyes; discard center of old plants
|
- Lamb’s Ear
(Stachys)
|
- Every 2-3 years, spring or early fall
|
- Spreading division; discard weak centers
|
- Lenten Rose
|
- Rarely, but in spring. Divide young plants while they are in bloom or immediately after
|
-
|
- Pinks
(Dianthus)
|
- Every 1-3 years, spring
|
- Spreading root system; division adds longevity to the plant
|
- Mums,
garden types
(Dendranthemum)
|
- Every year
|
- Will be most vigorous if divided and replanted annually; discard center core
|
- Sedum
(Sedum)
|
- When center weakens or for more plants, spring
|
- Clump divisions
|
- Tickseed
(Coreopsis)
|
- Every 1-3 years, spring or fall
|
- Spreading root division, discard old center
|
- Wormwood
(Artemisia)
|
- Every 1-2 years for spreading varieties, spring
|
- Spreading root division; discard old center; do not divide woody varieties
|
- Yarrow
(Achillea)
|
- Every 2-3 years or when the center dies out, spring or fall
|
- Spreading root division
|
