One of the simplest methods of propagating woody plants, as well as others such as climbers that have long, flexible stems, is known as layering. Stems form roots at points where they touch the soil. Some plants, such as strawberries and ivies, form layers naturally.
How do I propagate a plant
You can layer plants directly in the ground or prepare pots of potting mix (mixed with an equal volume of horticultural grit) that are placed near the plant. Choose a vigorous but flexible stem near ground level from around the perimeter of the plant. Bend it down to ground level and locate a point between two nodes or sets of leaves that will be in contact with the soil (or potting mix). Make a shallow cut in the bark on the under-side of the stem (if the stem is very thin, for instance if you are layering a clematis, the cut is not necessary). Pin the stem to the ground (or the surface of the potting mix) and hold it in place with a short length of stout wire bent into a U-shape or with a stone. Turn the tip of the stem upwards and tie it loosely to an upright cane
driven into the soil or potting mix
to encourage upright growth.
How long does it take the layer to root?
Layered stems can take anything between six to 12 months to form sturdy roots. To test for rooting, lightly pull on the stem. If you feel resistance, roots will have formed. Sever the stem from the plant, then pot the layer up or plant it out.
Which shrubs can be propagated by layering?
What is air-layering?
Air-layering is used where there is
no suitable stem that can be pulled
down to ground level. The stem is encouraged to produce roots well above ground level. It is often used
for houseplants where conventional techniques can be difficult.
How do I air-layer a plant?
Select a suitable stem from the previous year’s growth and strip off the leaves to create a bare length of 23–30cm (9–12in). Make a diagonal cut up to 4cm (11⁄2in) long in the underside of the stem. Lift up the tongue of bark, then pack with damp moss. Pack more moss around the stem and hold this in place with a plastic sleeve sealed to the stem at each end with insulating tape, lengths of wire or string.
To encourage rooting, it is necessary to exclude light – therefore, using black plastic should speed up the process. However, if you use clear plastic, you can see when – and if – the stem has produced roots.
How long does rooting an air-layered plant take and how do I deal with the new plant once there is a good root system?
It can take up to a year, but check periodically for signs of rooting.
Try not to disturb the moss too much.
Check the plant in spring to see how good the roots are. If they are filling the plastic sleeve, you can sever the new plant from the parent, cutting just below the roots. Pot up the layer in a suitable potting mix, then trim back the topgrowth to create a balanced plant. Grow the plant on
for up to year, then plant out in its final position.
Which plants can be air-layered?
How to air-layer a plant
1: Choose a vigorous, healthy stem on which the branches are well spaced.
2: Locate a point on the stem between clusters of leaves. With a sharp knife, cut through the bark.
3: Make a parallel cut farther up the stem, then peel away the collar of bark with the tip of the knife.
4: Wrap damp spaghnum moss around the stem to cover the cut area completely.
5: Wrap a piece of plastic over the moss to hold it in place and keep
6: Tie the plastic in position at each end with lengths of wire to seal in the moss.
What are dropping and stooling?
These are two techniques used to propagate some soft-stemmed plants that tend to lose their leaves at the base of stems. Heathers (Erica) and woody herbs such as rosemary (Rosmarinus) and lavender (Lavandula) can be propagated by one of these methods. Both methods produce roots on an existing plant’s bare stems to create secondary plants. As with layering, the techniques are very reliable as the new plants remain attached to the parent until well rooted – which can take up to one year. No further aftercare is required.
When should I propagate a plant by these methods?
Autumn is the best time for dropping or stooling, though it can also be done throughout winter, provided the ground is not frozen or waterlogged.
How do I ‘drop’ a plant?
Dig up the plant and shake the roots free of soil. Dig a deeper hole that will accommodate the rootball and the lower, bare parts of the stems. Drop the plant in the hole. Leaf-bearing parts of the stem should be above ground level. Backfill with the excavated soil mixed with garden compost and sharp sand. New roots will form on the lower part of the stems that are under the soil.
Which plants are suitable
- Rhododendrons (small)
How to layer a plant
1: Find a flexible stem around the perimeter of the plant that can be bent down to ground level.
2: Hold the stem in place either with a piece of wire bent into a
U-shape or with a heavy stone.
3: Insert a cane near the stem tip and tie the stem to this to keep it upright. Dig up the layer when the roots are well developed.
How do I ‘stool’ a plant?
Prepare a mixture of equal parts garden soil, garden compost and sharp sand. Earth it up around the base of the plant so that all bare parts of the stems are covered. Leafy stem parts should be just above the mound. New roots will form part way up individual stems that are covered in earth.
Which plants are suitable
- Cotinus coggyria
- Hydrangea paniculata
Stooling a plant
1: Prepare a mix of equal parts garden soil, sand and peat or garden compost.
2: Mound this mix around the plant so that the bare parts of the stems are covered.