There are several advantages of taking cuttings to generate new plants. Firstly, the cuttings will have identical characteristics to the mother plant, so the sex, size, quality, smell, taste, strength etc will be known. The plants will also grow to a similar shape and size, so space can be used more efficiently. A further benefit is that once the initial outlay has been made for the seeds, new plants can be grown for a minimal cost.
Although any part of a plant can be used as a cutting, some parts will take longer to develop roots than others. The main head or arm tips have the highest concentration of growth hormones (auxins) and therefore more likely to root. Cuttings should be made from softwood stems and not the older, harder stems. ‘Softwood’ is the term which refers to the younger, soft, green stems. These are the easiest to root. Once these stems mature and age they are then known as ‘semi-ripe’’ and when fully mature, ‘hardwood’. Choose stems that are healthy and have at least three sets of nodes – smaller cuttings will root but they can be more difficult and may take longer, the ideal length is around 5 – 8 cms. Cuttings can be taken at any point in the vegetative stage of growth and in the first 3 or 4 weeks of the budding period. After this it may be difficult to get the cutting to root. NOTE: It is generally best to take more cuttings than required, you can then select the best ones or compensate for any that do not root.
MAKING THE CUT
Use a tool with a sharp blade to make the cut, a scalpel or razor blade for example. The blade should be sterilised to prevent contamination by bacteria etc, using a flame, alcohol or a bleach solution. Clean new blades to remove any grease etc. Make a 45° diagonal cut below the nodes, leaving a good section of stem underneath. Select as thick a stem as possible as thin cuttings can take longer to root.
If you are taking several cuttings at once, or if there will be a time delay between cutting and planting, take a larger cutting than is needed initially, and make the final cut later. Cuttings should be left sitting upright in water so that air does not get to the roots. Use a pair of scissors for the first cut, as the opposing blades will ‘seal’ the end. Make the final cut with a sharp blade (not scissors), this leaves an open cut which allows roots to develop.
REMOVING THE LOWER LEAVES
The larger, lower leaves should be removed, so the cutting does not have to expend energy maintaining them. They will probably die anyway. At least the top two sets of leaves must be left. It is preferable (if possible) to remove leaves before making the cut, to avoid embolisms. An embolism occurs when a small bubble of air is sucked up into the stem, preventing the cutting from drawing up the water, nutrients etc that it needs. This will also allow you to plant the cutting as soon as possible after it has been taken from the mother plant.