Plant cuttings reproduce exactly the parent plant and incidentally keep your garden well stocked at minimal expense. The principle is straightforward enough – to take a leaf, bud, section of stem or piece of root from a living plant and grow a new plant from it. The reason for there being different kinds of cuttings is that some species will propagate more readily from, say, a stem cutting rather than a root cutting, or more readily at one time of year rather than another. But many plants will happily reproduce from more than one type of cutting.
The various kinds of cuttings are encouraged to grow roots by different means, but all types have these requirements in common -light, warmth, moisture and a clean, free-draining soil. The soil usually provided is a seed and cuttings compost, or a half-and-half mixture by volume of peat and coarse sand. The amount of warmth needed varies according to the type of cutting and the plant species, but 13-18°C (55-65°F) is usually considered adequate. A dusting of hormone rooting powder over the base of the cutting before planting will also help it to take root.
A good many plants may be propagated by leaf, leaf-bud or root cuttings, but by far the most widely used are those taken from stems. They should never be too short, for the infant plant needs food reserves to see it through until it takes root. The longer the rooting time, the longer the cutting needs to be. The shortest cuttings – some 2-4in – are from softwood. These are taken in the spring and early summer when growth is vigorous and the cutting will root quickly.
Intermediate-length cuttings are from semi-ripe wood, usually taken in late summer when growth is not so vigorous and the cutting needs greater food reserves to maintain it until the roots form; these cut¬tings are generally made 6-8in long.
Most widely used of all are the hardwood cuttings, which are generally planted outdoors and may take a year to root. Their food requirements are the greatest of all, and consequently they are 9-12in long.
Everything about cuttings techniques is concerned with the race between rooting and plant starvation. Thus all kinds of stem cuttings are made just below leaf nodes. Cellular activity is strongest there and roots will form more rapidly from such a wound. By the same token, it is best to strip most of the leaves from the cutting, allowing only a few to remain at the top. This will cut the amount of moisture lost through transpiration, while the remaining leaves will add to the food reserves through photosynthesis. It’s all a matter of balances.
Rooting time for different types of cuttings
This list will give you some idea, but remember that different species take different
times to ‘strike’ – take root – and growing conditions too will have an effect.
Stem cuttings – 3-6 weeks.
Leaf-bud cuttings – 3-6 weeks.
Leaf cuttings – 6-10 weeks.
Softwood cuttings – 4-8 weeks.
Semi-ripe cuttings – 1-6 months (depending on when the cutting is made).
Hardwood cuttings – 5-12 months.
Root cuttings – 4-8 weeks.
Leaf-bud cuttings – 4-8 weeks.
Using Rooting Harmone Powder
Considering how very little rooting powders cost, why not give them a try? It’s true that they aren’t always necessary, but at the very worst they’ll have no effect at all, and at best, with nine cuttings out of ten, they’ll help. Rooting powders contain a growth hormone – usually naphthylacetic acid -which speeds up the production of callus tissue, the corky scar tissue that forms at the base,of a cutting. Some also incorporate a fungicide as a counter to rot. In most cases, the new roots develop from the callus, rather than from the plant tissue of the cutting.
Provided that the cutting has been correctly made, and that the growth conditions are adequate, most cuttings will root without the aid of a hormone. However, this can take a considerable time with some plants, and the longer it takes the greater the chance of the cutting dying from starvation or rot before it roots. So anything that speeds the process can only be of help.
Types of cuttings
In cuttings phraseology, the terms softwood, semi-ripe and hardwood are what infant, teenager and adult signify in people. That is, the terms refer to the same object at different stages of its growth. As the year progresses, the same young stem would be suitable for making each of these three types of cutting in turn.
These are taken very early in the growing season before there is any sign of hardening in the new shoot. They are green both at the tip and the base.
These are taken towards the end of the growing season (July-August), when the tip of the stem is soft and green but the base is hardening, browning and becoming woody.
These are taken between October and March when the stem has hardened and become woody throughout its length.
Three other terms used in cuttings jargon are heel, stem and tip. These define the part of the stem used for the cutting.
A type of cutting in which the stem is torn off in a way that retains a portion of the parent branch – a heel – at its base. Heel cuttings are most often made from softwood or semi-ripe wood. They are normally 2-8in long.
Most often used for hardwood cuttings. As hardwood cuttings, they normally include 9-12in of the stem to provide a reservoir of nutrients so that the cutting can survive through the winter until growth begins in spring. As softwood cut tings, they are normally 2-6in long, depending on the species.
Short portions – usually 2-6in long – taken from the tips of stems. These are the parts used for most softwood and semi-ripe cuttings.