Plant Propagation Techniques – Taking Plant Cuttings
There are several plant propagation techniques that can be used to increase your plant stock, and this article covers the plant propagation technique of.
Propagation by Cuttings
A simple way of propagating most shrubs is by taking mature stem, while many perennials can be grown from tip or .
The increase of plants by taking cuttings is probably the most widely practised type of vegetative propagation. A section of stem with or without leaves, a section of root or a single leaf or bud of a living plant is removed and treated in such a way that it develops into a new plant.
There are various types of cuttings, each with their own requirements, but certain general rules apply. For a cutting to strike —take root — it must have adequate light, warmth and moisture. Except in special cases, very small cuttings should be avoided as they tend to exhaust their food reserves before roots can be formed. Similarly, over-large cuttings draw up too much water and soon flag
The rooting medium for cuttings must be free-draining yet capable of retaining sufficient moisture, and it must permit free passage of air. It also has to be free of.
Plant Propagation Techniques – Tip cuttings
Some perennials, notably non-hardy plants such as Centaurea gymnocarpa, penstemon and dimorphotheca as well as foliage perennials such as chamomile (Anthemis) and rue (Ruta), are best increased from tip cuttings. Take these from the ends of non-flowering lateral shoots during late summer and early autumn. The rooted cuttings generally need protection during winter in a cold frame. Plants grown under glass can be increased from tip cuttings at any time of year.
Take the cuttings, 7.5-10cm (3-4in) long, from the tips of healthy, leafy stems, ensuring that each cutting has at least three leaf joints.
Fill a pot to just below the rim with John Innes seed, or a proprietary cuttings compost. A 10cm (4in) pot will take about six cuttings.
Trim each cutting just below the lowest leaf node, slicing through at right angles to the stem with a sharp knife or a razor blade. Pull off the lowest pair of leaves.
Make shallow planting holes in the compost with a pencil. Insert the cuttings so that the base of each stem touches the bottom of the hole, without burying the leaves. Firm in with your fingers.
Water the pot thoroughly from overhead, and label the cuttings. Cover the pot with a plastic bag and secure with a rubber band. To prevent the plastic coming into contact with the cuttings, construct a framework of sticks or looped galvanized wires before putting the plastic in place. Set the pots of cuttings in a shaded cold frame to root. Alternatively, put the cuttings in a propagating frame with a regulated bottom heat of about 16°C (61°F).
After four to six weeks — about three in a propagating frame — the cuttings should have rooted. To check, tug them gently. If they don’t yield, they have rooted and the plastic covering can be removed or the pots can be taken out of the propagator. Leave the pot of cuttings in the frame for four or five days, then remove from the pot by turning it upside-down and carefully dislodging the compost, together with the rooted cuttings, in one piece.
Separate the rooted cuttings carefully, then pot them up singly into 7.5cm (3in) pots of John Innes No. 1 potting compost. Firm in each cutting and water thoroughly. Allow the pots to drain before putting them in a shaded cold frame. Pinch out the growing tip of each plant after about a week to encourage the development of a strong root system instead of excessive top growth.
Overwinter the cuttings in a closed cold frame. Plant out in their growing positions in spring, when all danger of frost is over.
Plant Propagation Techniques – Basal cuttings
Most clump-forming perennials, such as bugloss (Anchusa), thrift (Armeria),, heleniums, lupins and scabious (Scabiosa), can be propagated not only by division, but also from the young shoots appearing from the base of the plant in spring.
Cut off some of these basal shoots when they are 7.5-10cm (3-4in) long, at crown level or just below. Insert the cuttings directly into thein a cold frame, or in 7.5cm (3in) pots containing a proprietary cuttings compost.
Keep cuttings well watered by spraying them from overhead, and keep the frame closed. As new growth starts to show, increase ventilation by gradually opening the frame.
After about six weeks, pot the cuttings singly in 9cm (3-1/2in) pots of John Innes No.1 potting compost. Plant them out in their permanent positions during autumn, after hardening off.
Plant Propagation Techniques – Semi-
Many woody shrubs and trees can be propagated successfully from cuttings taken in summer. These include actinidia vines, spotted laurel (Aucuba), caryopteris, Mexican orange (Choisya) and lavender ().
Semi-hardwood cuttings are made from the current year’s growth which has become moderately firm and woody towards the base but is still growing, so the tips of the shoots will be soft. The best time to take semi-hardwood cuttings is from mid to late summer. They require some attention from the time they are set out until they are rooted — their ideal position is in a cold frame, and close attention should be paid to watering and shading from the sun. A year or two must elapse before the plants are ready for their permanent quarters.
Take the cuttings by choosing 15-20cm (6-8in) long side-shoots of the current season’s wood — easily identified, as the shoots will have leaves growing on them. With a knife or secateurs, cut off a shoot close to the main stem. Remove the leaves from the lower part of the shoot and sever it just below the lowest leaf node. Trim off the soft tip above a leaf so the cutting is about 10cm (4in) long.
Other plant propagation techniques include: