Common Name |
Botanical Name |
When to Divide |
How to Divide |
Asters |
Need botanical name |
Spring. Every year or two to control spread and promote vigor. |
Divide root ball into smaller sections. |
Baby's Breath |
Gypsophila paniculata |
Not recommended to divide but Spring or late Summer or early fall. |
If you really want to try, make certain you do not cut the root by digging and carefully divide by hand. |
Baloon Flower |
Platycodon |
Late fall when it has died back or not appeared yet in Spring. |
Rarely do unless unavoidable- deep root system. |
Basket-of-Gold |
Aurinia saxatilis |
Divide in late summer/early fall. |
Divide root ball. Can also be propagated by stem cuttings in spring or late summer. |
Bears's Breech |
Acanthus |
Spring |
Divide roots into smaller clumps |
Beebalm |
Monarda |
Every 3 years to control rampant growth. Spring or fall. |
Spreading root division. |
Bellflower |
Campanula |
Every 2 to 3 years or as the plant becomes crowded. Spring or early fall. |
Divide roots into smaller sections |
Black Eyed Susans |
Rudbeckia Hirta |
Spring: 3-4 years |
Divide Clump into smaller sections |
Blackberry Lily |
Belamcanda |
Every 3 to 4 years after bloom is finished. |
Rhizome root division. Discard woody or rotted. (See Special Treatments) |
Blanket Flower |
Gaillardia grandiflora |
Every 1 or 2 years to maintain vigor. Early spring. |
Divide root ball into smaller sections. |
Bleeding Heart |
Dicentra |
Rarely needs division. Early spring. |
Divide by hand because the roots break easily.
Choose fleshy roots |
Cannas |
Canna |
Every 3 or 4 years. Can do more often. Spring. |
Choose fleshy roots. |
Cranesbill |
Geranium |
Every 2 to 4 years in Spring or Fall. |
Divide root ball into sections. |
Creeping Phlox |
Need botanical name |
Spring but after bloom or Fall |
Divide root ball into sections. |
Day Lily |
Hemerocallis |
Anytime but preferably after blooms -2-3 yrs. |
Move tuber segments. |
False Spirea |
Astible |
Every 2 to 3 years as plants become crowded. Early Spring or fall. |
Divide root ball into smaller sections. Needs division for best bloom. |
Ferns |
N/A |
Before or as the plant breaks dormancy. |
Rarely do unless unavoidable- deep root system. |
Garden Peony |
Paeonia |
Rarely do they need division and doing so may prevent blooms for 3 years. September or October. |
Divisions should have three to five well-developed eyes (buds for next years growth). Plant peonies with the eyes no deeper than 1 inch below the surface. |
Garden Phlox |
Phlox paniculata |
Every 3 to 4 years. Early spring or fall. Spreading root division. |
Divide roots into sections. |
Geranium, Hardy |
Geranium |
Divide in Spring or late summer/early fall. |
Need more research |
Iris, Bearded |
Iris Germanica |
Every 3 to 4 years. After flowering up to September. |
Rhizome root division. Discard woody or rotted. (See Special Treatments) |
Iris, Siberian |
Iris Sibirica |
Divide after blooming. Early Summer |
Rhizome root division. Discard woody or rotted. (See Special Treatments) |
Lambs-ear |
Stachys Byzantina |
Every 2 to 3 years. Spring or early fall. |
Divide outer area of root clump and discard weak centers. |
Lemon Balm |
Melissa officinalis |
Spring or fall but no later than October. |
Division of roots with 3 or 4 buds each. |
Lily, (Plantain) |
Hosta |
Rarely need division.They can be divided if you want more plants, however, they will reach their best performance if not divided too often. Early Spring or early fall. |
Pick the fleshy roots, divide into clumps with one to three eyes. A wedge can be taken from an established plant, which will soon fill back in. |
Lily (True Lily) |
Lilium |
Three to four weeks after they have finished flowering every 2-3 years. |
Dig carefully around root system as some lilies have shoots. Select the larger bulbs to transplant. If you have a good light source (a nursery or sun porch) the smaller ones can be nurtured to grow bigger for planting. |
Lily of the Nile |
Agapanthus |
Spring, summer or fall When flowering slows due to crowding. |
Fleshy clumping roots are large and brittle. Do not divide unless needed to improve bloom. |
Lily of the Valley |
Convallaria majalis |
Spring or fall. Divide for plant increase as desired. Early spring. Can be divided as clumps or single "pips". |
Keep the strongest pips and discard the old. Budgeters, keep the old and plant in an out of the way place. |
Lupin |
Lupinus |
Before or when the plant breaks dormancy. |
Rarely do unless unavoidable- they have a very deep root system. |
Mints |
Need to research more. |
* |
* |
Monkshood (aka Wolfbane) |
Aconitum Dephinifolium |
10+ years Spring |
Resents disturbance. DO WEAR RUBBER GLOVES WHEN DIVIDING TUBERS. The roots are poisonous and was once used to kill wolves, hense the the aka: Wolfbane. |
Ornamental Grasses |
N/A |
Spring only: 3-4 years |
Some grasses do not tolerate fall division. Due to the very dense fibrous roots you may require the use of an very sharp knife (be careful), saw or ax to divide. |
Poppy |
Pavaver |
After the foliage dies down. |
After extracting the plant cut the roots into 3- to 4-inch long pieces. They will need to remain in a cold frame for a few week in sandy soil. |
Peonies |
Paeonia |
Fall 10 - 12 yrs |
3-5 eyes (the pink buds on top of the clump)in one divide. |
Russian Sage |
Perovskia |
Before or when the plant breaks dormancy |
Do not do often. Very deep root system. |
Baloon Flower |
Platycodon |
Late Fall when it has died back or not appeared yet in Spring. |
Rarely do this. Not the best plant to transplant. |
Purple Cone Flower |
Echinacea Purpurea |
Every 4 years. Spring or fall. |
Divide roots. |
Red-hot-poker |
Kniphofia |
Divide only for plant increase. Spring or fall. |
Choose the flesh colored roots.Divisions may take 2-3 years to bloom.
|
Roger's Flower or Fingerleaf Rodgersia |
Rodgersia aesculifolia |
Spring or fall: 3-4 yrs |
Divide root ball into smaller sections |
Tall Garden Phlox |
Phlox paniculata |
Spring or fall: 3-4 yrs |
Divide root ball into smaller sections. |
Stone Crop |
Sedum (Autumn Joy) |
For plant increase. Spring. |
Divide root ball. Can do softwood cuttings or root leaves in early summer. |
Thyme, Garden |
Thymus vulgaris |
May to September |
Dividing old roots, or making cuttings, by slipping pieces off the plants with roots.
|
Tickseed |
Coreopsis |
Every 1 or 2 years to maintain vigor. Spring or fall. |
Divide roots |
Wormwoods |
Artemisia |
Every year or two. Spring |
Divide root and discard dead center. Do not divide woody artemesias. |
Mum |
Chrysanthemum |
Every year or two. Spring. |
Divide root ball into smaller sections. |
Rose Mallow |
Hibiscus |
Before or as the plant breaks dormancy. |
Rarely do unless unavoidable- deep root system. |
Yarrow |
Achillea |
Every 2 or 3 years or when center dies out. Spring or fall. |
Divide roots |