There are three main types of wood used for stem cuttings. Explain in your own words how you would tell if the cutting material was:
Growing plants for cuttings is most common method of propagation - that is, using pieces of vegetative plant material instead of seed.
To successfully grow plants from cuttings the following must apply:
- the plant must be capable of producing adventitious roots from some of the stem or, in the case of root root cuttings, to produce a new shoot system as well as a new root system.
- suitable healthy material must be chosen from the original plant and the original plant should not be stressed for any reason suck as lack of water when the cutting material is taken.
- the cutting have sufficient water and humidity, adequate light, without being exposed to excessive or direct sunlight and the rooting mix should be kept at the correct temperature.
1. Softwood
Softwood cutting are always made from soft growth and can be very fast to root (approximately two to three weeks). Although softwood cuttings often root more easily and quickly than other types of cuttings, require more care and attention. Typically, the cutting will be about 5 - 15cm long, although for some plants they may be shorter.
- Cutting treatment - remove leaves from the lower half of the cutting. The leaves which are larger can be reduced by 1/3.
- The material should only be gathered from stock plants with firm turgid growth and which are not under stress from dry conditions.
- Shorter side shoot should be chosen and a good test as to the suitability of the material is to bend the shoot, at a right angle.
- the cutting should be prepared and inserted into the propagation medium as soon as possible.
- softwood cutting can be made with a knife or a pair of sharp secateurs.
- for many species rooting often occurs within 2 - 4 weeks.
- humidity level must be maintained.
- hormones are often beneficial.
- fungicides maybe beneficial.
2. Semi-hardwood
Semi hardwood cutting are usually made from evergreen, trees, shrubs and stems that are intermediate between the softwood and woody stages. The latter occurs when the growth ripens and become mature. It is also depending on the degree of firmness, semi-hardwood cutting can be subdivided into :
1. Soft semi-hardwood : the shoots are still growing but their lower portions have taken on a degree
of firmness and they are becoming woody.
2. Firm semi-hardwood : much of the shoot is becoming woody.
- Semi-hardwood cutting are generally 5 - 15cm in length.
- Most semi-hardwood cuttings can be made with a knife or secateurs.
- take cutting from just below the node and leaves and site shoots are removed from the lower half of the cutting and if the large leaved plant, the leaves are reduced in size.
- the timing for taking semi-hardwood cuttings are throughout the year and depending on plant species.
- for some plants cuttings may try to make growth instead of producing roots and so may be quite slow to root.
- humidity levels must be maintained.
- hormones may be beneficial.
- fungicides may be beneficial.
3. Hardwood
They are made from mature wood that has become quite hard. The main plants propagated from hardwood cuttings are coniferous plants, but quite a wide range of native plants can be propagated through this method. Hard wood cutting are usually taken during late Autumn or best in early Winter when the plants are more or less dormant.
- hardwood cutting there are two kinds - those are rooted indoors are usually 12 - 18cm long and those that are rooted in open ground and are 20 - 25cm long.
- short hardwood cuttings are made in the same manner as semi-hardwood cuttings.
- long hardwood cuttings are selected from more vigorous growth because it is often difficult to obtain lateral growth that are long enough.
- the basal leaves and the side shoots are removed, leaving about one-third to one-quarter of the foliage.
- any soft tip growth should also be cut off as it will only wilt. The base of cutting is usually trimmed just below a node with a knife or a secateurs.
- humidity levels must be maintained.
- fungicide dips can be beneficial.
Describe in your own words how stem cuttings are prepared for propagation.
Growing plants from stem cutting is by far the most popular method of vegetative propagation. The main difficult about taking stem cutting is a stem, separated from its original plants, has to survive while it initiates and develop roots and establishes itself as a new plant. Usually a stem cutting has no support system from the original plant until we supply ourselves. Usually we should ensure that the propagating environment will not enhance root development but also maintain the cutting until it is self-supporting.
A stem cutting can be divided into five wood condition for the purposes of propagation:-
i] Softwood cuttings have leaves and are made from the first flush of growing in spring. Their stem are normally very soft because they have grown extremely environmental controls to minimise water loss until they become established.
ii] Greenwood cutting are made from the tips of the leafy stem during early to midsummer. Their stem are soft, although harder than softwood cuttings, and they are grow in the controlled environment.
iii] Semi-ripe cuttings are made in late summer from stem growth that are slowed and hardened but is still actively growing. Although their leafy stem stems are subjected to water loss, they can survive under less rigorous environmental controls than softer wood cuttings.
iv] Ripewood cuttings are stems taken from evergreen plants during winter. They have almost hardwood stems but, because they are leafy, they are not entirely dormant and will require some degree of environmental control.
v] Hardwood cuttings are made from leafless dormant stems of deciduous plants. They require a minimal environmental control for survival.
Wounding - wounding can be useful for semi-hardwood and hard-wood cuttings that are difficult to root, especially if they have older wood at their base. This is a traditional treatment. The thin layer of cells below the bark is called the cambium layer and this is where the new roots are formed during propagation.
Stem wounding which involves removing a thin slice of the stem which not greater that 1/3 of the stem). By removing this section of the stem a greater amount of the cambium layer is exposed and this method encourages faster root development.
The disadvantage of wounding as a treatment for cuttings is that the large wounded area increases the likelihood of the cutting becoming infected by diseases resulting in propagation failure.
Rooting Hormones - hormones are only beneficial if all the other factors are within the ideal range, such as good hygiene has been used, humidity and temperature levels are in correct range. The correct way to of rooting hormones can speed up the propagation process and improves rate on difficult to root species.
The naturally occurring hormone indolebutyric acid (IBA) are commonly used for rooting products. The approximate ratio 01% to 0.8% with the high concentration range are used for hardwood cuttings but apparently can damage the soft tissues and failure is cause on propagation.
Heel cutting - is a traditional way to propagate plants from stem cuttings. The reason for taking a stem cutting with a heel is to give the cutting a firm base so that is well protected against possible roots. It is widely used method of removing a stem cutting from a plant.
Heel cuttings are often used for stem cuttings that take some time to develop roots, for example those are planted in autumn and have to survive through the winter before rooting. Heel cutting can be taken at any time of a year.
Mallet cuttings - have a hardwood plug at the base of each cuttings to guard against rooting organism. it is most successfully made from stems with a feathered habit, that is from a stem with small side-shoots.
The nodal area of a plant stem contains a greater amount of carbohydrates or food reserves.
Prune back the original plant in winter to encourage vigorous stem growth, which has a high capacity to produce roots.
