Print Posted on 24/02/2017

An easy guide to propagating plants

An easy guide to propagating plants

Have you ever been to a friend’s house and seen a plant that you just love and wish you could have at home? With a bit of know-how, it may be possible to propagate the plant so you can grow it in your own garden.

Thanks to Sustainable Gardening Australia, here’s a quick guide to propagation.

Cuttings

A cutting is the term used for lengths of plant material being used specifically to propagate new plants. In contrast to growing plants from seed, where we may get plants that are slightly different from what we expected, cuttings will always be clones of the parent plant from which the cutting was taken – for example, a camellia cutting from a plant with a pink and white flower will produce another identical camellia with a pink and white flower.

Types of Plants suitable for Cuttings

All perennial and shrubby plants provide excellent potential for cuttings. The most successful plant material for cuttings comes from the ‘square’ stemmed plants eg from the Laminaceae family. This includes salvias, mint, rosemary and many other herbs. Many of the perennials in the daisy family, like Federation Daisies, also do well from cuttings however other daisy plants, like Echinacea sps, are best propagated from root division.

Taking cuttings

The preferred cutting length is about 10cm to 12cm with at least 2 to 3 nodes on each cutting. The lower cut should be on an angle just beneath the first node. You can also ‘nick’ the area just beneath the lower node taking care not to damage the node itself. This node will be below the soil surface and this is where the root zone will develop.

The top cut should be made above the next node (or the one above). The entire cutting length should contain 2 or 3 nodes in total. These upper nodes will be where the leaves of the new plant will shoot. Take care not to damage any of the nodes along the cutting length. Plant nodes have the amazing ability to produce either roots or leaves depending on whether they are above or below the soil level which is why cuttings are so effective.

Avoid taking cutting from any plant when it is in flower as these cuttings will have less potential for success.

Growing

Cuttings do best in a free draining mixture so that they don’t rot. It is best to put lots of cuttings in the same pot rather than single cuttings in many post. The warmth and humidity of having them all clustered together will help them to strike. To increase the warmth and humidity, and maintain heat overnight, if possible cover the pot with a clear plastic ‘hood’ or the end of a polystyrene bottle. If doing this, keep the pot out of direct sunlight so that the air inside in the pot doesn’t heat up too much and ‘cook’ the cuttings. Mist the cuttings regularly to help regulate the temperature and keep a moist environment.

Potting up

Leave the cuttings in the pot long enough for them to establish strong root systems. Remove any cuttings that start to look like they have failed so that you don’t allow rots and fungal problems to enter the pot. They will usually look weak, brown off and begin to rot at the base.

You can generally tell when the cutting has taken if it starts to put on new leaves and to grow. However be patient as the roots may take longer to develop. Continue to water the cuttings until you are ready to pot up.

You can test for roots by gently rocking the cutting. If you feel no resistance, then the roots have probably not yet developed.

When you think the cuttings are ready to pot up, tip the pot gently upside down and remove all of the contents together. Lay on a piece of newspaper and gently start to disentangle the roots. It is important to minimise the damage to these young roots as the vigour of the new plants depends on a strong root system.

Pot the young cuttings into small pots with a good quality potting mix. Water in with a weak solution of seaweed fertiliser or worm leachate tea. Put the cuttings in a sheltered spot to ‘harden off’ before gradually introducing them to a more open environment.

Once the root mass of the cutting starts to fill its new pot, either pot on again or, if the conditions are suitable, plant into a prepared garden bed.