University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln Nebraska Statewide Arboretum Publications Nebraska Statewide Arboretum 2019 Articles by Bob Henrickson: Dividing Perennials / Decorate Your Christmas Tree Naturally / Beatrice High School Arboretum Student and Community Involvement / Dried Flowers for Winter Crafts / Woody Floral Plants Brighten Outdoor Containers / Field Notes: Dwarf Chinkapin Oak / Field Notes: Liatris punctata / Fine- textured Perennials Can Take the Heat / Gardening with Prairie Plants / Grasses that Deserve More Attention / Herbs for the Landscape / Leadplant—A Garden-worthy Prairie Pioneer / Native Fruiting Trees & Shrubs for Wildlife / Oaks for Nebraska & Surrounding Great Plains / Outstanding Ornamental Grasses / Follow this and additional works at: https://digitalcommons.unl.edu/arboretumpubs The Pawpaw—North America’s Largest Native Edible Fruit / The ShagbarkHenrickson, Bob, Hickor "Articles by—Ay Bob Henrickson:Flavor unlik Dividinge PAnyerennials Other / Decor /ate Gr YeatPlantsTMour Christmas Tree for Naturally / Beatrice High School Arboretum Student and Community Involvement / Dried Flowers for WinterCurbside Crafts / GarWoodydens Floral Plants/ Pr airieBrighten Plants Outdoor ContainersUsed on / Field the Notes: Plains Dwar f /Chinkapin Prairie Oak / Field Notes: Liatris punctata / Fine-textured Perennials Can Take the Heat / Gardening with Prairie Plants /Plants Grasses thatfor Deser Rainve Mor Gare Adensttention / HerbsGrowing for the Landscape Trees with/ Leadplant—A RootMak Garden-worer®thy Prairie ContainersPioneer / Native F ruitingand TGrreesow & Shrubs Bags for /Wildlif Frome / Oaks the for Gr Nebroundaska & up Surr ounding/ Growing Great Plains / Outstanding Ornamental Grasses / The Pawpaw—North America’s Largest Native Edible Fruit / The WShagbarkoody Hickor Cutsy—A / Fla Recommendedvor unlike Any Other / Gr HareatPlantsTMdy Per forennials Curbside Garfordens X eriscaping/ Prairie Plants Used in on the Plains / Prairie Plants for Rain Gardens / Growing Trees with RootMaker® Containers and Grow NebrBags / Faskarom the Ground up / Growing Woody Cuts / Recommended Hardy Perennials for Xeriscaping in Nebraska" (2019). Nebraska Statewide Arboretum Publications. 23. Bobhttps:/ Henrickson/digitalcommons.unl.edu/arbor etumpubs/23 Nebraska Statewide Arboretum This Article is brought to you for free and open access by the Nebraska Statewide Arboretum at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Nebraska Statewide Arboretum Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Articles by Bob Henrickson Nebraska Statewide Arboretum Dividing Perennials The three main reasons for dividing become established. perennials are to control the size of the If you divide in the spring, allow plants, to help rejuvenate them, and to enough time for roots to settle in before hot increase their number. Dividing and weather. Spring division is ideally done in the replanting keeps rapidly spreading early spring as soon as the growing tips of the perennials under control. Dividing will plant have emerged. Spring divided rejuvenate old plants, keeping them vigorous perennials often bloom a little later than and blooming freely. Dividing perennials is an usual. easy and inexpensive way to gain additional Never divide perennials on hot, sunny plants for your garden or to share. days. Wait until a cloudy day, ideally with several days of light rain in the forecast. WHEN TO DIVIDE Most perennials should be divided In general, it is best to divide spring every three to five years. Some perennials and summer blooming perennials in the fall, such as chrysanthemums and asters may and fall bloomers in spring. By dividing the need to be divided every one or two years or plant when it is not flowering, all the plant’s they will crowd themselves into non- energy can go to root and leaf growth. flowering clumps of leaves and roots. Fall division should take place Bleeding hearts and peonies may never need between early September and mid-to late to be divided unless you want to increase October. Allow at least four to six weeks your stock. before the ground freezes for the plants to Signs that perennials need dividing common perennials. These can crowd out are flowers that are smaller than normal, their own centers. Some can be invasive centers of the clumps that are hollow and unless divided frequently. They can usually dead, or when the bottom foliage is sparse can be pulled apart by hand, or cut apart with and poor. Plants that are growing and shears or knife. blooming well should be left alone unless Large, vigorous more plants are wanted. plants with thickly intertwined roots may • PREPARE TO DIVIDE AHEAD OF need forceful separation TIME by watering the plants to be with digging forks. Put two divided thoroughly a day or two forks back to back in the before you plan to divide them. center of the plant and use Prepare the area that you plan to put them to pry the pieces your new divisions in before you lift apart. the parent plant. Divide the plants into clumps of three • Prune the stems and foliage to 6 to five vigorous shoots each. Small or weak inches from the ground in order to and woody divisions should be discarded. ease division and to cut down on Discard the center clump if it is weaker than moisture loss. the outside edges. • LIFT THE PARENT PLANT by using a sharp pointed shovel or spading fork CLUMPING ROOT SYSTEMS originate from a to dig down deep on all four sides of central clump with multiple the plant, about 4 to 6 inches away growing points. Many have from the plant. Pry underneath with thick fleshy roots. This your tool and lift the whole clump to group includes astilbes, be divided. If the plant is very large hostas, daylilies and many and heavy, you may need to cut it into ornamental grasses. several pieces in place with your It is often necessary shovel before lifting it. to cut through the thick fleshy crowns (the central • SEPARATE THE PLANT by shaking growing area between the or hosing off loose soil and remove roots and the leaves and stems of the plant) dead leaves and stems. This will help with a heavy, sharp knife. You can also pry loosen tangled root balls and make it apart these roots with back to back digging easier to see what you are doing. forks. Keep at least one developing eye or Perennials have several different types of bud with each division. If larger plants are root systems. Each of these needs to be wanted, keep several eyes. treated a bit differently. RHIZOME DIVISION Rhizomes are stems that grow horizontally at SPREADING ROOT or above the soil level. SYSTEMS have many Bearded irises are the most slender matted roots common perennial with this that originate from type of root system. Divide many locations with irises any time between a no distinct pattern. month after flowering until Plants with spreading early fall. root systems include asters, bee balm, lamb’s ear, purple cornflowers and many other Cut and discard the rhizome sections gas plant ( Dictamnus albus ), Japanese that are one year or older. Also, inspect anemones, false indigo ( Baptisia ) and rhizomes for disease and insect damage. columbines ( Aquilegia ). Damaged rhizomes should be trimmed and Lenten and Christmas roses treated, or discarded if too badly damaged. (Helleborus ) are very difficult to move when Iris divisions should retain a few more than a few years old. Usually you can inches of rhizome and one fan of leaves, find tiny seedlings around the base. These are trimmed back halfway. Replant with the top easy to move. of the rhizome just Lavender cotton (Santolina showing above soil chamaecyparrus ) and several other level. perennials are actually small woody shrubs and should not be divided. These include TUBEROUS perennial candytuft ( Iberis sempervirens ), ROOTS lavender, rosemary, southernwood (Artemesia abrotanum ), and several other Dahlias are artemesias. These plants often have rooted an example of perennials with tuberous roots. layers (branches that have developed roots The tubers should be cut apart with a sharp while touching the soil). The layers can be cut knife. Every division must have a piece of the off the parent plant, dug up and replanted as original stem and a growth bud attached. though they were divisions. After division they can either be replanted or stored for spring planting. PLANT THE DIVISIONS and never allow divisions to dry out. Keep a pail of water DIVIDING LARGE, TOUGH ROOTS nearby to moisten divisions until they are If the root mass is very large, or tight planted. Trim all broken roots with a sharp and tangled, you can raise the clump 1 to 2 knife or pruners before replanting. feet off the ground and drop it. This should Plant the divided sections loosen the root mass, and you can pull the immediately in the garden or in containers. individual plants apart. This is not a good Replant divisions at the same depth they method for plants with brittle roots such as were originally. Firm soil around the roots to peonies. eliminate air pockets. Water well after Plants that have very tough, vigorous planting. root systems (agapanthus, red-hot pokers Fall-divided perennials should be and ornamental grasses) may have to be mulched in the upstate the first winter to divided with a shovel, saw or ax. You can also prevent heaving caused by alternating vigorously hose off soil to make the root shallow freezing and thawing of the soil. The system easier to work with. best winter mulch is loose and open such as pine straw, Christmas tree limbs or leaves. DON’T DIVIDE THESE PERENNIALS Some plants resent being divided and it should be avoided if possible. These include butterfly weed (A sclepias ), euphorbias, oriental poppies, baby’s breath (G ypsophila ), Decorate Your Christmas Tree Naturally Whether they are eye-popping mantle members. But if you want nature inside for displays, gorgeous wreaths, or topiary trees, the holidays, you must begin collecting early.