Plant Propagation by Stem Cuttings

Introduction

Types of Stem Cuttings

Procedures for Rooting Stem Cuttings

 

 

Introduction

 

Propagation by stem cuttings is the most commonly used method to propagate many woody ornamental plants. Stem cuttings of many favorite shrubs are quite easy to root. Typically, stem cuttings of tree species are more difficult to root. However, cuttings from trees such as crape myrtles, some elms, and birches can be rooted.

A greenhouse is not necessary for successful propagation by stem cuttings; however, maintaining high humidity around the cutting is critical. If rooting only a few cuttings, you can use a flower pot (Figure 1). Maintain high humidity by covering the pot with a bottomless milk jug or by placing the pot into a clear plastic bag. Cuttings can also be placed in plastic trays covered with clear plastic stretched over a wire frame (Figure 2). Trays must have holes in the bottoms for drainage. The plastic will help keep the humidity high and reduce water loss from the cuttings.

 

Figure 1.
Figure 2.

 

Types of Stem Cuttings

The four main types of stem cuttings are herbaceous, softwood, semi-hardwood, and hardwood. These terms reflect the growth stage of the stock plant, which is one of the most important factors influencing whether or not cuttings will root. Calendar dates are useful only as guidelines. Refer to Table 1 for more information on the best time to root stem cuttings of particular ornamental plants.

Table 1. Optimum stage of tissue (wood) maturity for rooting stem cuttings of selected woody ornamentals

Evergreen Plants

Common Name

Scientific Name

Type of Cutting

Abelia

Abelia spp.

SH, HW

Arborvitae, American

Thuja occidentalis

SH, HW

Arborvitae, Oriental

Platycladus orientalis

SW

Azalea (evergreen & semi-evergreen)

Rhododendron spp.

SH

Barberry, Mentor

Berberis x mentorensis

SH

Barberry, Japanese

Berberis thunbergii

SH, HW

Barberry, Wintergreen

Berberis julianae

SH

Boxwood, Littleleaf

Buxus microphylla

SH, HW

Boxwood, Common

Buxus sempervirens

SH, HW

Camellia

Camellia spp.

SW, SH, HW

Ceanothus

Ceanothus spp.

SW, SH, HW

Cedar

Cedrus spp.

SH, HW

Chamaecyparis; False Cypress

Chamaecyparis spp.

SH, HW

Cotoneaster

Cotoneaster spp.

SW, SH

Cryptomeria, Japanese

Cryptomeria japonica

SH

Daphne

Daphne spp.

SH

Eleagnus, Thorny

Elaeagnus pungens

SH

English ivy

Hedera helix

SH, HW

Euonymus

Euonymus spp.

SH

Fir

Abies spp.

SW, HW

Gardenia; Cape jasmine

Gardenia jasminoides

SW, SH

Heath

Erica spp.

SW, HW

Hemlock

Tsuga spp.

SW, SH, HW

Holly, Chinese

Ilex cornuta

SH, HW

Holly, Foster's

Ilex x attenuata 'Fosteri'

SH

Holly, American

Ilex opaca

SH

Holly, Yaupon

Ilex vomitoria

SH

Holly, English

Ilex aquifolium

SH

Holly, Japanese

Ilex crenata

SH, HW

Jasmine

Jasminum spp.

SH

Juniper, Creeping

Juniperus horizontalis

SH, HW

Juniper, Chinese

Juniperus chinensis

SH, HW

Juniper, Shore

Juniperus conferta

SH, HW

Leyland cypress

x Cupressocyparis leylandii

SH, HW

Magnolia

Mahonia spp.

SH

Oleander

Nerium oleander

SH

Osmanthus, Holly

Osmanthus heterophyllus

SH, HW

Photinia

Photinia spp.

SH, HW

Pine, Mugo

Pinus mugo

SH

Pine, Eastern white

Pinus strobus

HW

Pittosporum

Pittosporum spp.

SH

Podocarpus

Podocarpus spp.

SH

Privet

Ligustrunum spp.

SW, SH, HW

Pyracantha; Firethorn

Pyracantha spp.

SH

Rhododendron

Rhododendron spp.

SH, HW

Spruce

Picea spp.

SW, HW

Viburnum

Viburnum spp.

SW, HW

Yew

Taxus spp.

SH, HW

SW = softwood, SH = semi-hardwood, HW = hardwood

 

Deciduous Trees

Common Name

Scientific Name

Type of Cutting

Azalea (deciduous)

Rhododendron spp.

SW

Basswood; American linden

Tilia americana

SW

Birch

Betula spp.

SW

Bittersweet

Celastrus spp.

SW, SH, HW

Blueberry

Vaccinium spp.

SW, HW

Broom

Cytisus spp.

SW, HW

Callery pear

Pyrus calleryana

SH

Catalpa

Catalpa spp.

SW

Clematis

Clematis spp.

SW, SH

Crabapple

Malus spp.

SW, SH

Crape myrtle

Lagerstroemia indica

SH

Cherry, Flowering

Prunus spp.

SW, SH

Dawn redwood

Metasequoia glyptostroboides

SW, SH

Deutzia

Deutzia spp.

SW, HW

Dogwood

Cornus spp.

SW, SH

Elderberry

Sambucus spp.

SW

Elm

Ulmus spp.

SW

Euonymus

Euonymus spp.

HW

Forsythia

Forsythia spp.

SW, SH, HW

Fringe tree

Chioanthus spp.

SW

Ginkgo, Maidenhair tree

Ginkgo biloba

SW

Goldenrain tree

Koelreuteria spp.

SW

Hibiscus, Chinese

Hibiscus rosa-sinensis

SW, SH

Honey locust

Gleditsia triacanthos

HW

Honeysuckle

Lonicera spp.

SW, HW

Hydrangea

Hydrangea spp.

SW, HW

Ivy, Boston

Parthenocissus tricuspidata

SW, HW

Larch

Larix spp.

SW

Lilac

Syringa spp.

SW

Maple

Acer spp.

SW, SH

Mock orange

Philadelphus spp.

SW, HW

Mulberry

Morus spp.

SW

Poplar, Aspen; Cottonwood

Populus spp.

SW, HW

Poplar, Yellow; Tulip tree; Tulip poplar

Liriodendron tulipifera

SH

Quince, Flowering

Chaenomeles spp.

Sh

Redbud

Cercis spp.

SW

Rose of Sharon; Shrub-althea

HIbiscus syriacus

SW, HW

Rose

Rosa spp.

SW, SH, HW

Russian olive

Elaeagnus angustifolia

HW

Serviceberry

Amelanchier spp.

SW

Smoke tree

Cotinus coggygria

SW

Spirea

Spiraea spp.

SW

St. Johnswort

Hypericum spp.

SW

Sumac

Rhus spp.

SW

Sweet gum

Liquidambar styraciflua

SW

Trumpet creeper

Campsis spp.

SW, SH, HW

Virginia creeper

Parthenocissus quinquefolia

SW, HW

Weigela

Weigela spp.

SW, HW

Willow

Salix spp.

SW, SH, HW

Wisteria

Wisteria spp.

SW

SW = softwood, SH = semi-hardwood, HW = hardwood

Herbaceous cuttings are made from non-woody, herbaceous plants such as coleus, chrysanthemums, and dahlia. A 3- to 5-inch piece of stem is cut from the parent plant. The leaves on the lower one-third to one-half of the stem are removed. A high percentage of the cuttings root, and they do so quickly.

Softwood cuttings are prepared from soft, succulent, new growth of woody plants, just as it begins to harden (mature). Shoots are suitable for making softwood cuttings when they can be snapped easily when bent and when they still have a gradation of leaf size (oldest leaves are mature while newest leaves are still small). For most woody plants, this stage occurs in May, June, or July. The soft shoots are quite tender, and extra care must be taken to keep them from drying out. The extra effort pays off, because they root quickly.

Semi-hardwood cuttings are usually prepared from partially mature wood of the current season’s growth, just after a flush of growth. This type of cutting normally is made from mid-July to early fall. The wood is reasonably firm and the leaves of mature size. Many broadleaf evergreen shrubs and some conifers are propagated by this method.

Hardwood cuttings are taken from dormant, mature stems in late fall, winter, or early spring. Plants generally are fully dormant with no obvious signs of active growth. The wood is firm and does not bend easily. Hardwood cuttings are used most often for deciduous shrubs but can be used for many evergreens. Examples of plants propagated at the hardwood stage include forsythia, privet, fig, grape, and spirea.

The three types of hardwood cuttings are straight, mallet, and heel (Figure 3). A straight cutting is the most commonly used stem cutting. Mallet and heel cuttings are used for plants that might otherwise be more difficult to root. For the heel cutting, a small section of older wood is included at the base of the cutting. For the mallet cutting, an entire section of older stem wood is included.

Figure 3.

 

Procedures for Rooting Stem Cuttings

Cuttings should generally consist of the current or past season’s growth. Avoid material with flower buds if possible. Remove any flowers and flower buds when preparing cuttings so the cutting’s energy can be used in producing new roots rather than flowers. Take cuttings from healthy, disease-free plants, preferably from the upper part of the plant.

The fertility status of the stock (parent) plant can influence rooting. Avoid taking cuttings from plants that show symptoms of mineral nutrient deficiency. Conversely, plants that have been fertilized heavily, particularly with nitrogen, may not root well. The stock plant should not be under moisture stress. In general, cuttings taken from young plants root in higher percentages than cuttings taken from older, more mature plants. Cuttings from lateral shoots often root better than cuttings from terminal shoots.

Early morning is the best time to take cuttings, because the plant is fully turgid. It is important to keep the cuttings cool and moist until they are stuck. An ice chest or dark plastic bag with wet paper towels may be used to store cuttings. If there will be a delay in sticking cuttings, store them in a plastic bag in a refrigerator.

While terminal parts of the stem are best, a long shoot can be divided into several cuttings. Cuttings are generally 4 to 6 inches long. Use a sharp, thin-bladed pocket knife or sharp pruning shears. If necessary, dip the cutting tool in rubbing alcohol or a mixture of 1 part bleach to 9 parts water to prevent transmitting diseases from infected plant parts to healthy ones.

Remove the leaves from the lower one-third to one-half of the cutting (Figure 4). On large-leafed plants, the remaining leaves may be cut in half to reduce water loss and conserve space. Species difficult to root should be wounded.

Figure 4.

Treating cuttings with root-promoting compounds can be a valuable tool in stimulating rooting of some plants that might otherwise be difficult to root. Prevent possible contamination of the entire supply of rooting hormone by putting some in a separate container before treating cuttings. Any material that remains after treatment should be discarded and not returned to the original container. Be sure to tap the cuttings to remove excess hormone when using a powder formulation.

The rooting medium should be sterile, low in fertility, and well-drained to provide sufficient aeration. It should also retain enough moisture so that watering does not have to be done too frequently. Materials commonly used are coarse sand, a mixture of one part peat and one part perlite (by volume), or one part peat and one part sand (by volume). Vermiculite by itself is not recommended, because it compacts and tends to hold too much moisture. Media should be watered while being used.

Insert the cuttings one-third to one-half their length into the medium. Maintain the vertical orientation of the stem (do not insert the cuttings upside down). Make sure the buds are pointed up. Space cuttings just far enough apart to allow all leaves to receive sunlight. Water again after inserting the cuttings if the containers or frames are 3 or more inches in depth. Cover the cuttings with plastic and place in indirect light. Avoid direct sun. Keep the medium moist until the cuttings have rooted. Rooting will be improved if the cuttings are misted on a regular basis.

Rooting time varies with the type of cutting, the species being rooted, and environmental conditions. Conifers require more time than broadleaf plants. Late fall or early winter is a good time to root conifers. Once rooted, they may be left in the rooting structure until spring.

Newly rooted cuttings should not be transplanted directly into the landscape. Instead, transplant them into containers or into a bed. Growing them to a larger size before transplanting to a permanent location will increase the chances for survival.

 

 

For Further Reading


Published by:

Erv Evans, Extension Associate & Frank A. Blazich, Professor; Department of Horticultural Science North Carolina Cooperative Extension Service

 


 

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Última actualización: 20 de marzo de 2002