I love growing perennials. This is because perennials require less maintenance. Plant it once and enjoy it every year. However, infrequent maintenance does not mean that it does not require maintenance.
After a few years in the ground, many perennials need some attention at the end of the season. As it grows, growing taller and wider, it becomes overcrowded, produces fewer flowers, develops dead spots, and reduces growth. It’s easy to mistake these signs for other problems, and fertilizing won’t fix them, but dividing them will.
By digging up and dividing your perennials every few years, you not only get free plants out of them, but also revitalize them and keep your plant stock healthy for longer.
Plants that benefit from autumn division
Fall is the best time to divide ornamental and edible perennials that bloom in spring and early summer. Autumn usually involves less gardening work than spring. You can see exactly where your plants are growing, how big they are, and where you have free space in your garden so you can replant your divisions. The warmth remaining in the soil during colder temperatures reduces transplant shock, and higher rainfall increases the chances of new transplants surviving.
Plants with bulbs, rhizomes, or large, fleshy roots are usually better for fall division because they have more energy stored for winter.
Divide perennials about 4 to 6 weeks before the ground freezes in your climate. This will allow time for roots to establish before the plant goes dormant.
Below is a list of common perennials that should be lifted and divided in the fall.
allium
When to divide: Every year or as needed Note: Divide when the leaves start to wither.
artichoke
Divide period: Once every 3 to 5 years Note: Separate the child plant from the parent plant and replant.
aster
Divide period: Once every 1 to 3 years Note: Replant small plants from the outside of the plant.
astilbe
Divide period: Once every 1 to 3 years Note: Divide the plants regularly to improve flowering.
strawberry without fruit
Split time: Every year or as needed
bearded iris
When to divide: Every 1 to 3 years Note: Cut rhizomes into 3- to 4-inch sections containing at least one “fan” of leaves and roots.
black eyed susan
Stock division period: Once every 4 to 5 years
Blanket flower (gaillardia)
Stock division period: Once every 3 to 5 years
Cornflower (Echinacea)
Divide period: Every 4 to 5 years Note: Transplanted plants are likely to bloom in the second year.
Sangobell (Heuchera sanguinia)
Divide period: Once every 1 to 3 years Notes: Discard the woody part in the center
Cornflower
Stock division period: Once every 1 to 3 years
Cranesbill (Geranium)
Stock division period: Every 6 to 10 years
creeping lily lawn
When to divide the plants: Every year or as needed Precautions: Divide the plants to prevent them from becoming too aggressive.
creeping phlox
Divide period: Once every 1 to 3 years Note: Replant only stems that have not become woody.
Dwarf hollyhocks (Sidalcea spp.)
Stock division period: Once every 1 to 3 years
bubble flower
Stock division period: Once every 1 to 3 years
goldenrod
Stock division period: Once every 4 to 5 years
chicken and chick
When to divide: Every year or as needed Notes: Separate the small outer rosette from the parent plant and plant.
Wasabi
When to divide the plants: Every year or any time Note: Divide the plants when the leaves wither.
Hosta
Stock division period: Every 6 to 10 years
jack in the pulpit
When to divide the plants: Every year or any time Note: Divide the plants during the dormant period.
Jerusalem artichoke
When to divide the plants: Every year or any time Note: Divide the plants when the leaves wither.
joe pie weed
Stock division period: Once every 1 to 3 years
women’s cloak
Stock division period: Every 6 to 10 years
lamb’s ears
Stock division period: Once every 4 to 5 years
Liguraria
Stock division period: Every 6 to 10 years
Lily (lily)
Split time: annually or as needed
Masterwort (Astrantia sp.)
Stock division period: Once every 4 to 5 years
mint
Divide period: Once every 3 to 5 years Note: Divide the stock to prevent it from becoming too aggressive.
oriental poppy
Stock division period: Every 6 to 10 years
peony
Division timing: every 10 years or as needed
Periwinkle
Split time: annually or as needed
Primrose
Split time: annually or as needed
Rosemallow (perennial hibiscus)
Division timing: every 10 years or as needed
Sage (Salvia sp.)
Divide period: Once every 6 to 10 years Note: Divide the plant when the center of the plant dies.
shasta daisy
Stock division period: Once every 1 to 3 years Note: Please discard the old center part.
siberian iris
When to divide: Every 6 to 10 years Note: Cut leaves back to 6 to 12 inches before dividing.
summer snow
Stock division period: Once every 1 to 3 years
mountain snow
Stock division period: Once every 1 to 3 years Caution: Divide the stock to prevent it from becoming too aggressive.
Seal of Solomon
Stock division period: Every 6 to 10 years
speedwell
Stock division period: Once every 3 to 5 years
sweet woodruff
Split time: annually or as needed
tall phlox
Divide period: Once every 2 to 4 years Precautions: Please discard the dead or woody core.
Tickseed (Coreopsis)
Stock division period: Once every 1 to 3 years
violet
Split time: annually or as needed
wild ginger
Stock division period: Every 6 to 10 years
