How to Propagate Carnations from Cuttings and Layers

Why this is maintenance, not a hobby

A carnation is a short-lived perennial that peaks early. The first year builds the plant, the second gives the best flowers on the strongest stems, and from the third the base goes woody, the stems get shorter and fewer, and the flowers arrive later and smaller. That is normal and it cannot be fed or pruned away. A collection that looks good year after year is one where new plants are constantly coming through from cuttings.

The practical consequence is that you should take cuttings every single year, from every plant you want to keep, whether or not the parent looks like it needs replacing. It takes half an hour and it means an ageing plant can be scrapped without hesitation the moment it stops earning its place. Gardeners who skip this end up nursing tired plants because they have nothing to replace them with.

Cuttings also solve the identity problem. Carnations do not come true from seed, so the only way to keep a color or a form you like is to take material from that exact plant. Seed is worth sowing for interest and for new combinations, but never as a way of keeping something you already have.

Taking cuttings from non-flowering shoots

Use side shoots that have not run up to flower, taken from the middle of the plant rather than the very bottom or the very top. Four to five inches (10 to 13 cm) long, firm but not woody, with the leaves still close together on the stem, is the right material. Shoots from the base are often too soft and rot; shoots from near an old flower stem are too hard and sit for weeks without rooting.

The traditional method is to pull rather than cut. Hold the main stem in one hand, grip the side shoot low down, and pull sharply downwards so it comes away at a joint with a small heel of tissue. That joint is where roots form most readily. If a shoot will not pull cleanly, cut it just below a joint instead, which works nearly as well.

The best time is straight after the main flush, when there is plenty of non-flowering growth and the weather is still warm enough for quick rooting. Cuttings taken then root in three to four weeks and are established well before the cold. Cuttings taken late in the season root slowly, sit wet, and are the ones that rot over winter.

1. Choose the right shoot A non-flowering side shoot four to five inches (10 to 13 cm) long from the middle of the plant, with short joints and firm tissue. Avoid anything soft, hollow or already showing a bud.
2. Pull it off at a joint Hold the stem steady and pull the shoot sharply downwards so it parts at a leaf joint. A small heel of tissue at the base is ideal, and roots form fastest there.
3. Strip the lower leaves Take off the bottom two or three pairs of leaves, leaving a clean inch (2.5 cm) of stem. Leaves left below the surface rot and take the cutting with them.
4. Insert into a gritty mix Half potting mix and half sharp sand or perlite. Push each cutting in an inch (2.5 cm) deep, firm around it, and space them so no leaves touch.
5. Keep bright, shaded and barely moist Bright indirect light, out of direct sun, at around 60 to 65F (16 to 18C). Do not enclose them tightly; carnation cuttings rot in a sealed humid environment faster than they dry out.
6. Check for roots at three weeks A gentle tug that meets resistance means roots. Pot each rooted cutting into a three inch (8 cm) pot of gritty mix and grow it on cool and bright.

Layering, which suits the border kinds

Layering works on plants with long enough side stems to reach the ground, and it has the advantage that the shoot stays attached to the parent while it roots, so nothing wilts and nothing needs daily attention. It is slower than cuttings but the success rate is higher, and it is the safest method if you have only one plant of something and cannot afford to lose the material.

Choose a flexible non-flowering side stem, strip the leaves from the section that will touch the soil, and make a shallow slanting cut halfway through the stem at a joint so that the cut stays slightly open. Peg that section down into a shallow depression filled with gritty mix, cover it with an inch (2.5 cm) of the same, and put a stone on top to keep it firm.

Roots form at the cut joint over six to eight weeks. Once new growth is clearly coming from the tip of the layered shoot, sever it from the parent but leave it in place for another two weeks before lifting it, so it adjusts to standing on its own roots before being moved.

Where seed and division fit, and where they do not

Seed germinates readily at around 65 to 70F (18 to 21C) in a week or two, and raising a batch is genuinely worth doing for the variation it produces. What it will not do is reproduce a plant you already have. Every seedling from a good plant is a different plant, and most will be less good than the parent. Treat seed as a way of getting new things, not of keeping old ones.

Division is the method that most gardeners try first because it works on so many other perennials, and it disappoints here. A carnation forms a woody base rather than a clump of independent crowns, so pulling it apart usually gives you pieces with plenty of top growth and almost no roots, which then collapse. On a young plant with several soft basal shoots you may get away with it, but cuttings are quicker and far more reliable.

Whatever the method, label everything at the moment you take it. Carnation foliage is identical across colors, and a tray of unlabelled rooted cuttings is a tray of unknowns until it flowers a year later. Write the parent plant and the date on the label and put the label in before you insert the cuttings, not afterwards.

Do not take cuttings from a plant that has had rust or stem rot. The material carries the problem into the next generation and into your propagation area. Take from clean plants only, and if the plant you want is the diseased one, layer a shoot from the healthiest part instead and watch it closely.

Records that keep the cycle running

Note the date each batch was taken, the parent plant, and the date roots appeared. After two seasons you will know your own rooting time to within a few days, which lets you plan the batch so the young plants are ready to go out at the right point rather than sitting too long in small pots.

Keep a simple count of how many of each batch rooted. A batch where a third failed points at material that was too soft or a mix that held too much water, and the number is what tells you that. Note also which parent each surviving plant came from, so that in three years you can still trace a good plant back to its origin.