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How to…layer plants

by Rhiannon James

layering_plants_head

Sowing seeds and taking cuttings are two well-known ways to propagate plants: an option you might be less familiar with is layering. This is a method of growing new plants from stems that are still attached to their parent plant.

This technique has the advantage that the new plant is supported by the parent until a sustainable root system has formed, when the link between them can be severed. The process happens naturally with plants such as raspberries and ivy and is a super-easy, usually successful way to produce a few, well-developed new shrubs.

There are three main layering methods:

1. Simple layering: a cut is made on a low-growing stem which is then buried under the soil. A new system of roots will develop from the wound and eventually a new plant can be cut from the parent.

2. Air layering: a cut is made on a stem but rather than covering it in soil, the wound is wrapped in moss and plastic and the roots develop above ground. This technique is useful if the plant has upright stems.

3. Tip layering: a shoot tip is simply covered in soil and left to root.

Simply creating a sharp bend in a stem can sometimes induce it to produce roots as the flow of nutrients is restricted. But the process can be further encouraged by wounding the stem: either by removing a ring of bark or by making an incision in the stem.

When to do it

Layering can be done in the spring, using mature growth from the previous season, or in late summer / autumn, using the semi-ripe shoots of that season. Tip layering is best done in mid to late spring.

Things you’ll need

1. A sharp knife

2. A spade

3. Horticultural grit or sand

4. Organic material such as well-rotted compost

5. Matchsticks or toothpicks

6. Strong wire which can be bent into ‘staples’

7. Hormone rooting powder

And for air layering:

8. Sustainably-sourced sphagnum moss

9. Black polythene

10. Sticky tape

Step-by-step

Simple layering

1. The first step is to identify a stem that is young, supple and low-growing so it can be bent down to the ground without snapping.

2. Mark the point where the stem will reach the soil and dig over this area, adding grit and organic material to encourage more effective rooting.

3. About 30cm from the shoot tip and just below a leaf bud / node, remove a small sliver of bark from the underside of the stem or make a notch and prop it open with a matchstick or toothpick (strip the leaves from around this area but leave them in place at the shoot tip). Apply a little hormone rooting powder to the cut to stimulate rooting.

4. Dig out a small, shallow trench, about 15cm deep in which you can bury the stem. The trench should slope so that the wounded section of stem is buried at the deepest point and should end with a vertical to encourage the tip of the stem to grow upwards.

5. Bend the wounded part of the stem into the trench and peg it down using strong wire ‘staples’.

6. Cover this part of the stem with soil but leave the tip exposed (you can bend the tip into a vertical position and stake it in place). Firm the soil in well, making sure the stem has not lifted up. Water well if the soil is dry.

7. It’s important to keep the soil well-watered over the summer, during which time the root system for the new plant will form.

8. In the autumn (if you started the process in the spring), remove some soil and check if a good root system has formed. If it has, you can cut the connecting branch and leave the new plant to establish on its own.

9. You can then move the new plant to its final spot in the garden or into a pot for growing on.

Air layering

1. Select a healthy stem that’s roughly the diameter of a pencil. Pick a spot just below a leaf joint, about 30cm from the tip, and, using a sharp knife, trim off any leaves and side shoots from a 15cm section on either side. Then remove a sliver of bark from the stem or make a notch angled towards the stem tip and prop it open with a matchstick or toothpick. Apply hormone rooting powder to the cut to stimulate rooting.

2. Wrap two good handfuls of sphagnum moss (which has been soaked overnight) around the wound and squeeze until you form a solid ball. Then wrap black polythene around the ball, tying sticky tape around the top and bottom to hold it in place. This creates a warm, moist environment. It can help to cover the plastic if it’s exposed to the sun.

3. When a good root system has formed that’s visible through the moss (this can take up to a year), remove the polythene and cut the new plant from the parent close to the point of layering. Pot up the new plant in compost (do not try to remove the moss from the roots) and water.

4. Keep the new plant in a sheltered position and water regularly until it’s ready to plant out.

Tip layering

This method is used for plants such as Rubus, which can also perform this process naturally.

1. In spring, prepare the soil where you will be encouraging the shoot tip to root by adding grit and well-rotted compost. Choose a long stem that easily reaches the ground.

2. Dig a hole about 10cm deep where the stem touches the soil.

3. Insert the stem tip into the hole and pin it down with strong wire staples.

4. Cover the tip with soil, firm it in and water if dry.

5. In early autumn, check the tip has rooted. If it has, you can remove the layer and plant it immediately in well-prepared soil. If not, leave until the spring. Keep the new plant well-watered to prevent any risk of drying out until it’s well-established.

Plants suitable for layering

A-air layering; S-simple layering; T-tip layering

Akebia (A)

Camellia (S) and (A)

Carnations – after flowering in mid-summer (S)

Clematis (A)

Cornus (S) and (A)

Cotinus (S) and (A)

Daphne (S) and (A)

Forsythia (S) and (A)

Heathers (S)

Honeysuckle (S)

Japanese maples (A) and (S)

Jasmine (S) and (A)

Lilac (S)

Magnolia (S) and (A)

Rhododendron (S) and (A)

Rubus (T)

Viburnum (S) and (A)

Vitis (S)

 

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