If you want the best results from cutting propagation, you really need to pay attention to selecting the appropriate technique for the time of year, and type of plant you are growing. Different tissues have varying abilities to sprout roots and shoots and turn into a new plant.
The ease with which particular tissue can grow as a cutting depends upon the chemical and physical make up of that tissue. These physical and chemical properties can be extremely variable at different times of the year, under different environmental conditions, and even between different varieties of the same plant species; let alone from one part of a plant to another. To become more and more successful at cutting propagation; you need to strive towards appreciating these subtle differences. In time, a good cutting propagator can develop an ability to make informed guesses as how to propagate different plants.
Cuttings can be classified in different ways:
According to the time of year the cutting is taken (or the stage of growth the plant is at when it is taken). Example: A softwood cutting is one taken in spring when the young growth on the plant is soft tissue.
According to the type of plant tissue which is used. Example: A leaf cutting is a cutting made from just a leaf, or part of a leaf; and a stem cutting is made from a piece of stem.
According to the age or tenderness of the tissue being used.
Example: Softwood cuttings come from tissue that is soft; whereas hardwood cuttings come from harder wood, which is older.
The classification of cuttings is not always the same from country to country, or even place to place within a country. Terms used in one place are sometimes different to those used elsewhere. The term “tip” cutting is often used to describe a cutting taken from the end of a stem. This in effect normally, but not always, is the same as a softwood cutting.
Some cuttings might contain different types of tissue in the one cutting. A heel cutting, for example, can contain wood that has grown recently at the top (still soft); wood that is semi hard in the middle, and a small section of hard wood (from last years growth) attached at the bottom.
TYPES OF CUTTINGS
STEM CUTTING TECHNIQUES
A section of stem, usually (but not always) with some leaves left on the top but low leaves removed. There should be a node (this is a point at which a bud emerges) at the bottom of the cutting and at least another node at the top of the cutting. There may be one, or several nodes in between. The techniques of Softwood, Hardwood, Semi-hardwood and Root cuttings are covered in more detail later in this section. The techniques of Softwood, Hardwood, Semi-hardwood and Root cuttings are covered in more detail later in this section. Only these are covered in more detail, due to the significance of these techniques to commercial practices. Stem cuttings are usually softwood, semi hardwood or hardwood.
Usually these are called soft-tip cuttings. They are stem cuttings taken from new growth that is soft. This commonly occurs during spring, but may occur at other times of the year if suitable material is available. Common softwood cuttings include many common temperate climate shrubs including Myrtus, Hebe, Nerium, Magnolia, Weigelia, Spirea, and Maples; plus an extensive range of tropical foliage plants. Note: Semi Softwood cuttings are taken from tissue that is in the process of changing from soft to semi hardwood.
These are sometimes called half-ripe cuttings, or green wood cuttings. Semi hardwood cuttings are usually taken in late summer or early autumn, when recent spring growth is in the process of hardening. Many shrubs are propagated this way, including; Azalea, Camellia, Pittosporum, Grevillea, Euonymus, Prostanthera, Boronia, Ilex, and many Australian native shrubs.
Sometimes called ripe cuttings, they are taken in winter from old growth that is hard. Common hardwood cuttings include tip growth from conifers (eg: Juniperus or Chamaecyparis), or sections of stem from deciduous plants (eg: Rosa, Tamarix, Cydonia or Punica, Vitis, Ficus and many deciduous plants).
Stem cuttings can be taken from different parts of a stem.
They might be taken from the very tip, with the terminal (end) bud left attached (or in some cases removed).
They might be taken from sections of stem lower down, with the soft growing tip removed. In this case, several cuttings might be made from one single section of stem.
Another alternative is to pull a short side shoot, from a stem, with some older tissue still attached to the base. This older tissue is called a heel.
Some plants will even grow from sections of old stem (ie. wood that is 2 or more years old.
These are leafy stem cutting taken from a soft wooded (succulent growing) plant such as a Chrysanthemum, Aster, Coleus, Dianthus, Geranium, Pelargonium and many perennials & herbs. These can be taken virtually at any time of the year.
Stem cutting taken from the growing tip of a plant. Softwood cuttings are often tip cuttings. This plant material is very soft and prone to limp quickly (eg Weigela).
A stem cutting of 1 year old wood which has attached to the base, a small section of two year old wood. This section of older wood is called a heel. Normally prepared by tearing side shoots from a small branch or stem. The torn section is then trimmed neatly with a pair of secateurs or a knife (Abelia, Cotinus, Actinidia)
This is a stem cutting without a heel, where the base of the cutting is made as a right angle cut, just below a node (ie. where the leaf joins the stem). The section of stem containing the bud(s) (one or two nodes) may planted beneath the propagation media, with the leaf and part of the stem protruding above the surface. A single node cutting (also called leaf bud cutting) utilises a single node and a leaf as part of the cutting. The node may have one or two buds depending on the species being propagated. Examples of plants grown by single bud node cuttings include: Vitis, Magnolia, Passiflora, Camellia. Double bud nodes plants include: Lonicera, Clematis, Pandorea.Double node cuttings are made from plants where two leaves emerge at the same point along the stems length, but on opposite sides of the stem. The cutting retains two pairs of buds that are opposite each other. Double node cuttings are popular for climbing plants in that if one bud fails to shoot, the other might succeed. Lonicera, Clematis, Jasminum are commonly propagated by these methods.
Stem cutting where the base of the cutting is made at the point where the young shoot joins the older branch. At this point there is often some swelling in the stem. The basal cutting does not necessarily contain any older wood, as does the heel cutting. A range of plants that benefit for this types of cutting treatment include Acer, Cornus, Prunus.
A small section of cane from the plant, containing only one or two nodes, and no leaves is inserted horizontally (instead of vertically -like cuttings are normally done); with a bud showing just above the surface of the media. This is used with plants such as Saccharum (Sugar Cane), Cordyline, Dracaena and Dieffenbachia where it is difficult to obtain large quantities of cutting material. Heating & misting are usually essential for commercial success.
LEAF CUTTING TECHNIQUES
Lead Bud Cuttings
A full leaf (leaf blade and stalk) with a small piece of the stem the leaf was attached to. At the junction of the stem, there is a bud (which is retained). This technique is most commonly used when large numbers of plants need to be produced, but the quantity of propagating material available is limited. Plants which can be grown this way include:
Either a section of a leaf or a full leaf including the leaf stalk (ie. petiole) is used to produce a new plant. In the case of a section of a leaf being used (eg. Begonia, Gloxinia or Peperomia), the cutting must include part of a major leaf vein. New growth (a shoot and root) will normally grow from the base of the cutting (ie. the base of the leaf stalk, or the base of the leaf vein). Saintpaulia are commonly grown from full leaves. Some bulbs (eg. Lachenalia & Muscari) can be grown by leaves chopped into sections along their length. Other plants propagated by this technique:
Primula (many –not all)
Sections of relatively young (1-3 year old) root, 2-10cm long, taken preferably from young plants. Cuttings are planted horizontally at 2-4cm deep in the propagation media. Small delicate roots should be shorter and planted shallower (maybe a 1cm layer of sand over the top). Larger roots can be longer, and planted deeper. Many herbaceous plants are grown commercially from root cuttings in some parts of the world; but only a few wood species. Root cuttings may grow from many woody trees and shrubs, such as Albizzia,, some Daphne, Malus, some Populus, Rhus, Liquidambar, Syringia, and Wisteria), but are only occasionally used. Generally, any plants that produce suckers can also be grown by root cuttings.
There are different types of bulbs, and appropriate cutting propagation techniques will vary from one to another. True bulbs are plants that have a series of scales (like an onion). There are two types of bulbs. Tunicate bulbs have a sheath (or a covering called a tunic) that encases the bulb. Non tunicate bulbs have no tunic. There are other plants that also develop swollen underground sections. like a bulb, but are in fact not bulbs, because they are not made up of scales. These plants are often loosely grouped with and called bulbs. They include such things as corms (eg. gladioli), tubers (eg. potato) and rhizomes (eg. some iris). This type of cutting has one main requirement: that it has a bud (ie. “eye”), on each cutting, from which a shoot can emerge. Gladioli, potatoes and dahlias are just a few plants that can be grown this way.
There are four main techniques used for bulb cuttings – scaling, twin scaling, sectioning and basal cuttage.
Scaling involves removing individual scales from scaly (untunicate) bulbs. These segments may be treated with a fungicide (eg. sulphur powder) to control disease. Scales are then either planted (in pots or trays of propagating media) or placed in a moist bag of and put in a dark, cool location. Roots and a new bulblet will form at the base of the scale where it was broken from the bulb.
Twin scaling is used for non-scaly (tunicate) bulbs. It involves where the selected bulb is first prepared by the removing of any external outer brown tunic. The top section of the bulb is then normally cut off – this allows easier separation of segments later. The mature bulb is cut vertically into 8 or 10 sections; each having part of the basal plate. Each of these sections can be further divided by cutting down between the scales in effect leaving two scales connected to a small segment of basal plate. Treating cut bulbs with a sulphur dust fungicide is recommended. This is then placed in a bag of moist vermiculite until bulblets form (about 3 months). At this stage they can then be planted into trays and grown on.
Sectioning involves cutting a bulb vertically so that each section has pieces of scale attached to basal plate. Depending on the size of the bulb, you might obtain anything from 4 to 8 or more cuttings from one bulb. Daffodils and Jonquils can be grown successfully this way.
Basal Cuttage involves making cuts to expose tissue at the bottom of a bulb. From these cuts root and stem (or bulblet) growths may emerge, given the right conditions.
Scoring involves making cuts across the basal plate of a bulb, that are deep enough to destroy the flower bud that is dormant in the centre of the bulb.
Scooping involves removing the entire basal plate, by scooping it out of the bottom of the bulb (including the flower bud in the centre)
Coring involves cutting the central core and flower bud out of the basal plate. Any of these techniques will result in the energies of the remaining tissues going completely into vegetative growth, and the production of several to many new bulblets.
Any cut surfaces should be treated with a fungicide to minimise rot.
Where to plant Bulb Cuttings
You can plant any bulb cuttings vertically into a propagation tray with just the tips showing, irrespective of the type of cutting (eg. scaling, twin scaling, sectioning or basal cuttage)
Plants that can be grown this way include:
Narcissus ….taking a section of basal plate with scale or tissue above it
Basal cuttage (ie. Scoring, Coring or Scooping)
Crinum (some types
The emerging shoots of plants are used for softwood cuttings.
Although most plants produce soft new growth generally in spring, this is not necessarily true for all plants. The genus and species in conjunction with the climate can alter the time period.
Pruning techniques used on mother stock plants can also govern when softwood cuttings are taken.
These young shoots are tender and weak, prone to quick death if allowed to dry out after being removed from the plant. For this reason when the plant material is taken, it is usually removed from the plant early in the day and placed immediately in a cool moist environment (ie a bucket of water). Plant material taken is generally larger than what is needed – this is later cut to size during the softwood cutting process.
Soft plant tissue is easily bruised so careful handling and harvesting is essential. Extremely soft tissue that wilts the moment it is cut from the plant is not recommended as the success is often low and often rots on the propagation bench.
Softwood cuttings are traditionally taken about 50-120mm long (2-5inches) with several nodes. With misting, fogging and base heating equipment, softwood cuttings care now shorter at around 30-40mm (about 1.5 inches).
A weak concentration (1000-3000ppm) of rooting hormone is used which increases the success rate.
The tug test is used to indicate when the cutting has formed roots. This is when a gentle tug upwards of the cuttings is performed – if the cutting offers some resistance then the cutting has roots; if no resistance then no roots.
After rooting has occurred, watering (misting, etc) is reduced.
SEMI HARDWOOD CUTTINGS
After a growth flush has occurred, the plant tissue commences to lignify. Before it attains the point of hardening, when it is still flexible but firm, the plant tissue is referred to as semi hardwood.
Generally this occurs between early spring and summer – but is also dependent on the species of the plant and the local climatic conditions.
Very soft tips of these semi hardwood cuttings are generally removed as this soft tissue can desiccate during the rooting time period and increase chances of disease. Additionally this limp soft tip may interfere with water penetration to the rooting media.
Cuttings are usually 80-150mm (3-6 inches) long with the basal leaves removed.
Top leaves can be trimmed, but conflicting evidence indicates no clear benefit to this practice.
Hormone treatment is recommended to maximise root uniformity and success. Concentration will be dependant on species being propagated.
Hardwood cuttings may be performed on evergreen plus deciduous plants.
For deciduous plants, after the leaves have fallen (autumn or fall) through to late winter are the best times cuttings can be taken.
The cutting needs to be thick enough to store ample ‘food’ reserves for over wintering. As the cutting has no roots this cutting will be relying on what is stored it the stem.
Treatment of the cutting is variable – the technique chosen will depend on plant species, cultural methods used by a propagator. Hormones are usually used in the range of 2000-5000ppm. Some of the more common techniques include:
Bottom heat:- Tops of cuttings are exposed to cool temperatures but roots are kept warm at ?? oC (70oF). Cuttings are hormone treated, left for about 4 weeks and transplanted after callusing but before bud break.
Plastic bag:- Cuttings treated with hormone then sealed in a plastic bag and placed in dark at ??oC (50oC). Cuttings planted out after callusing.
Winter treatment:- Cuttings are bundled together and planted up-side-down in the soil outdoors, completely covered. In spring the bundles are dug up and planted the right way up.
Warm temperature:- Cuttings area treated with hormone, kept moist at around ??oC (70oF) for up to 5 weeks. After this treatment, the cuttings is usually stored until spring and planted out.
Outdoor ground beds:- Cuttings were made and treated then planted into outdoor base-heated ??oC (70oF) ground beds.
Most plants that produce suckers can be grown by root cuttings; however, in many instances, other propagation methods are also effective and are preferred.
For most root cuttings, it is important that you maintain an awareness of the proximal and distal ends of the cutting; and plant the cutting with the proximal end upwards.
Note: Proximal…refers to end of cutting closest to the stem
Distal…refers to end of cutting furthest from the stem
Five distinct types of root cutting propagation
Natural Suckering without Division -The type of plant that produces root suckers close to the stem or trunk.
Natural Suckering with Division -This includes plants (mostly shrubs) that sucker from roots that have NOT been damaged. They tend to sprout new shoots from roots naturally, and then connecting roots die back leaving the new plant independent of the parent.
Induced Suckering This type shoots a new stem from a root that has been damaged (perhaps by weeding, cultivation, lawn mowing, or even an animal or insect).
In situ whole Root Cuttings These plants produce a shoot from a section of root that has been severed from the parent plant, and left in situ until a shoot emerges from the proximal end (ie. cut roots around a stock plant, and severed sections of root that have no shoots attached will grow). Once the growth has sufficiently established the new plants can be dug up.
Ex Situ Detached Root Cuttings Here roots are dug up cut into short sections, then planted either in the open ground, or in containers.
Learn More about Plants through an ACS Plant Variety course.
Click for details: http://www.hortcourses.com/courses/product_listings.aspx?catid=Plant+Varieties