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Cass County Extension

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Vegetative Propagation of Perennials

Achillea: Divide clumps every 3-5 years; spring. Take cuttings in early summer.

Artemesia: Divide every 2-3 years; early spring as new growth is emerging. Decline after 5 years. Stem cuttings in early summer.

Astilbe: Divide clumps every 3-4 years; spring. 2-3 eyes per division.

Babysbreath: Difficult to divide because of taproot. Cuttings in early summer; treat with a rooting chemical and put under a mist.

Ballonflower: Flesh root can be diivided in spring, but with difficulty; doesn't require frequent moving. Cuttings treated with a rooting chemical start easily under mist in early summer.

Bellflower: Divide every few years in spring; 2-3 inch tip cuttings after flowering (C. glomerata).

Bergenia: Divide after 3-4 years of flowering; spring.

Blanketflower: Divide in early spring; every 2-3 years to prevent overcrowding. New growth that appears away from the old crown can be dug and transplanted; root cuttings can also be used.

Bleeding Heart: Divide every 3-5 years; early spring or early September. Fleshy roots are tender; handle with care. Cut into sections with 2-3 or 3-5 eyes per division. Cuttings can be taken in early summer. Root cuttings can be taken after flowering; should be three inches or more in length.

Boltonia: Divide in spring; tip cuttings can be taken in spring.

Brunnera: Divide in spring; can take 1 1/2 inch root cuttings in spring.

Butterfly Flower: Difficult to divide; tap root; tip cuttings in early summer.

Candytuff: Divide ib early spring; cuttings taken in early summer.

Chrysanthemum: Take plantlets from base of mother plant every year or two; spring before May 15th. Discard old plants; lose vigor with age. Three inch cuttings can be taken in late spring.

Columbine: Carefully divide tender roots every 3-5 years; late August- early September or early spring. Older clumps cab be divided but the resulting plants are less vigorous and shorter lived than seedlings. Self sow in moist soil; transplant seedlings in the spring.

Coral Bells: Divide natural sections every 4-5 years; spring. Stem cuttings in early June. Leaf cuttings, taken in mid summer, with part of the stem attached, root easily.

Coreopsis: Divide clumps every 3-4 years or when overcrowded; spring or fall. Basal softwood cuttings can be made in spring.

Croccus: Dig and reset when overcrowded; early October.

Cushion Spurge: Division in the spring should be done carefully so there is minimum damage to the thick fleshy roots; tip cuttings can be taken after flowering.

Daffodil: Dig and reset every 2-3 years to prevent overcrowding; September.

Daylily: Divide when overcrowded; late summer- early fall; at least 3 stems per division. Crown should be 1" below soil level.

Delphinium: Divide in early spring;.plants lose vigor after 2-3 years. Cuttings in early summer.

Echinacea (Purple Coneflower): Divide in early spring.

Erigeron (Fleabane): Divide clumps in spring; tip cuttings in the spring.

Eryngium (Sea-holly): Can be divided but not easy; tap root.

Feverfew: Divide regularily; spring. Cuttings in spring or summer.

Flax: Divide small clumps in spring; large clumps are hard to divide. Cuttings in mid summer.

Flowering Onion (Allium): Dig and reset bulbs when overcrowded; fall.

Gas Plant: Difficult to divide; carrot-like tap root.

Geranium (Crane's Bill): Divide every 3-5 years to renew vigor; spring best but can be done in September. Cuttings in summer.

Globe Thistle: Can be easily divided in the spring, in spite of their carrot-like roots. Root cuttings in the spring.

Goat's Beard: Clumps may be divided in the spring.

Golden Marguerite: Divide every 2-3 years or when overcrowded; early spring. Cuttings can be taken in mid summer.

Goldenrod: Divide every 3-4 years; early spring. Basal cuttings in fall; tip cuttings in spring. Self seeds; may become a nuisance.

Grape Hyacinth: Dig and reset when overcrowded; late September- early October.

Heliopsis: Divide every 2-3 years; spring. Stem or basal cuttings in spring.

Hollyhock Mallow: Divide in spring.

Hosta: Divide every 5-8 years; just after emergence. 2-3 eyes per division; eyes just below soil surface.

Hyacinth: Dig and reset every 2-3 years or when overcrowded; late September.

Bearded Iris: Divide every 2-3 years; late July- August. Use rhizome segment with leaf attached.

Siberian and Spuria Iris: Divide rhizomes every 5-10 years; don't allow to dry out when transplanting.  August (Siberian) and September or early spring (Spuria).

Jacob's Ladder: Divide in early spring or late summer; stem cuttings in mid summer.

Joe-pye Weed: Divide in spring.

Lady's Mantle: Divide in spring.

Liatris: Divide tuberous roots in early spring; every 3-4 years.

Lilies : Reset hardy bulbs every 3-4 years; late August. Small bulbs, bulbils and scales will flower in 2-3 years after planting.

Lungwort: Divide roots just after flowering when overcrowded; mulch transplants for winter.

Lupines: Divide or take hardwood cuttings in spring; don't transplant well.

Maltese Cross: Divide every 3-5 years; early spring.

Marsh Marigold: Divide in early spring.

Meadow Rue: Divide in spring.

Meadowsweet: Divide in spring; need frequent division to prevent over crowding. Daughter plants easy to move.

Missouri Primrose: Divide when overcrowded; spring. Prefers to be undisturbed.

Monarda: Divide every 3-5 years to maintain vigor; spring just as new growth emerges. New shoot cuttings; spring.

Monkshood: Divide in spring; slow to increase in size.

Mountain Bluet (Centaurea): Divide every 2-3 years; spring or fall.

Obedient Plant: Divide every 2-3 years; early spring. Cuttings in late spring.

Oriental Poppies: Dislikes being moved. Divide in late August as plants start to regrow; every 4-6 years. Mulch for 1st winter. 2" pencil diameter root cuttings can be taken; fall or spring.

Ostrich Fern: Divide large plants in spring, before growth starts.

Painted Daisies: Divide every 2-3 years; spring or late August. Stem cuttings; spring.

Pasque Flower: Seldom needs dividing. Divide root; early spring. 2' small root pieces will produce plants.

Penstemon: Don't require frequent division. Divide; early spring or fall. Stem cuttings from side shoots; mid summer.

Peony: Divide clumps in late August- early September; 3-5 eyes per division. Top eye no more than 2" deep. If divided in spring, may not bloom the same year.

Perennial Aster: Divide every two years in spring; lift clump and replant the vigorous outside growth and discard older center section. Tip cuttings in spring or early summer.

Phlox: Divide every 4-5 years to prevent overcrowding; early spring before growth begins. 3-5 vigorous shoots with roots per division. Stem cuttings; spring. 2" root cuttings; fall.

Ratibida (Prairie Coneflower): Divide in the spring.

Rudbeckia: Divide every 3-5 years; spring.

Russian Sage: Tip cuttings can be taken in summer; maintain humidity with plastic tent.

Salvia (Sage): Divide in the spring; slow to recover because of the long stringy root system. Softwood cuttings work well.

Sea Lavender (Statice): Can remain undisturbed for long periods; divide in early spring.

Shasta Daisy: Divide every other year; early spring. Stem cuttings; fall.

Showy Sedum: Divide clumps; early spring. 2-3" stem cuttings; early summer.

Sneezeweed: Divide every 2-3 years to prevent over crowding; early spring.

Snowdrop Anemone: Infrequent division needed. Divide roots in early spring.

Spiderwort: Divide every 2-3 years; spring.

Tulips: Dig and reset bulbs every 2-3 years; late September-early October. Set small bulbs 3-4" deep; Larger bulbs 5-6" deep. Need at least 3 weeks to root; larger the bulb the better it will flower.

Veronica: Divide clumps after 2-4 years of flowering; spring or early fall. Stem or basal cuttings; early summer

Viola: Divide after 3-4 years of flowering; early spring. Offsets can be taken in spring.

Virginia Bluebells: Divide tuberous roots in early fall; never let dry out. Plant 1" below soil level.


Todd Weinmann, Extension Horticulturist & Master Gardener Coordinator
Phone: (701) 241-5707
E-mail: todd.weinmann@ndsu.edu

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