1 Prune some low branches off the parent plant during the dormant season to induce vigorous growth.
7 Return the soil to the trench to bury the stem. Firm it in well.
2 Cultivate the soil well round the plant during the following late winter/early spring. Add peat and grit.
8 Water well, using a watering can with a coarse rose. Keep the soil moist, especially in dry periods.
3 Trim the leaves and side-shoots off a young, vigorous stem for about 4-24 in behind the growing tip.
9 Sever the layered stem from its parent plant in autumn.
4 Bring the stem down to ground level and mark its position on the soil 9 in behind its tip.
5 Dig a trench from that point. Make one straight side 4-6 in deep. Slope the other towards the plant.
6 Bend the stem at right angles 9 in behind its tip. Peg it down in the trench against the straight side.
10 Cut off the growing tip from the rooted layer about three to four weeks later.
11 Lift the layered stem if its roots are well advanced. Otherwise, leave for a further year.
12 Replant either in the open ground or in a pot and label. Leave to establish.
Air layering is one of the oldest artificial techniques of vegetative propagation. More than 4,000 years ago, it was tried in China and, because of its continued use in that country, it has traditionally been called Chinese layering. It is also sometimes referred to as marcottage from the great era of French gardening in the late seventeenth and eighteenth centuries.
An unpruned stem on a normally growing woody plant is induced to develop roots by restricting the stem about 6-9 in behind its growing tip and then excluding light. This combination will cause the initiation of roots, and, if the roots are surrounded by moist, warm soil, then they will develop. The stem is then severed from the parent and established as a new plant.
As a technique, air layering can be used on a wide range of plants that have woody stems, and it is a useful way of producing plants without specialized equipment or disturbing them unduly. It is carried out either in spring on the matured wood of the previous season, in which case layering is close behind the growing point, or in the late summer on the hardening shoots of that season's growth.
Select a stem of the current year's growth. Trim any side-shoots off the stem for about 6-12 in behind the tip.
I hen girdle the stem (see page 54) so that food and hormones build up in the region where rooting is required—usually about 9 in behind the tip. Treat the stem or the cut surfaces with hormone powder to improve rooting.
The most effective rooting medium is sphagnum moss as it holds water, is well aerated and is readily manipulated. Soak the moss overnight so that it is completely moist. Take two large handfuls of moss and squeeze it, then work it into a ball so that all the fibres are interwoven. When it reaches about 2^ in in diameter, split it in half, using the thumbs in the same way as an orange is divided. Place the two halves around the treated area of the stem and knead them together again so that the moss stays firm.
Hold the moss in place with a square of black polythene, and secure it to the stem with sticky insulating tape. It is important to ensure that moisture cannot run down into the moss and so waterlog it. So, turn the tape spirally round the ends of the polythene, overlapping it until it covers part of the stem.
The black polythene will retain moisture, maintain a warm environment, exclude light and allow gases to permeate the moss.
The layered stem will usually take at least a growing season to produce adequate roots.
4 Split the moss ball into two in the same way as an orange is divided.
5 Place the two halves round the treated area of the stem. Knead them together once more.
6 Hold the moss in place with a square of black polythene. Secure with sticky insulating tape.
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Prune back any new growth on the rooted layer towards the end of the dormant season. Then cut off the stem with secateurs just below the point of layering and remove the black polythene square.
The most critical stage when air layering is to establish the rooted layer successfully. Fill a pot with John Innes No. 1 compost or similar (see page 12). Slightly loosen the moss ball and roots. Place the rooted layer in the pot. Firm so the roots are in contact with the compost. Do not firm too heavily and so compress the moss ball and roots. Label and place in a protected environment until further root growth develops and the new plant is established.
1 Trim any leaves and side-shoots for about 6-12 in behind the tip of the stem to be layered.
2 Girdle the stem to encourage root formation (see page 54). Then treat it with rooting hormone.
3 Squeeze two handfuls of wet sphagnum moss together. Knead into a ball of about 2j in diameter.
7 Prune back any new growth on the rooted layer towards the end of the dormant season.
8 Cut the stem just below the point of layering, using a pair of secateurs. Remove the black polythene square.
9 Loosen the moss ball and roots slightly. Then pot in John Innes No. 1 compost. Firm in gently and label.
Tip layering lip layering is a specialized technique used for the various members of the genus Rul)as, such as blackberries and loganberries. If the growing tip of such a plant is buried in the soil, it will naturally swell, develop roots and establish itself. This phenomenon is modified to suit the gardener.
Tip layering is an invaluable technique for propagating a few plants, as it can be carried out in the garden on one part of a plant without disturbing the flowering or fruiting ability of the rest of it.
The members of the genus Rubus, especially the fruiting varieties, are prone to virus infections, and they should be propagated only from known virus-free stocks.
Select a new strong stem as it develops from the crown of the plant during the spring. As soon as it reaches 15-18 in long, pinch out the tip to encourage branching. The growth of these stems is rapid and vigorous, and soon the stems can be pinched out again. Continue to do this until midsummer, when about six to eight tips should be well developed.
It is at this stage that the stems can be layered. However, as the roots of these particular plants are fine, fibrous and easily damaged, the soil for layering should be well prepared so that once the layers have rooted they can be lifted with minimum damage to their root system.
1 Pinch out the tip of a
15-18 in basal shoot of the current year's growth.
2 Continue to pinch out the tips until six to eight tips have developed.
3 Cultivate the soil well. Add peat and grit to the top 6 in of the soil.
7 Cut back the original stem at the crown of the parent plant in September.
8 Cut off the rest of the stem once the rooted layer has dropped its leaves.
9 Shorten some of the top growth that the layer may have made.
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Dig and cultivate the soil thoroughly, if possible dig in a deep layer of organic matter to conserve moisture and prevent the roots drying. Improve the top 6 in by adding some peat and grit.
Pull down a stem and make a mark where its tip touches the ground. Start digging a trench at this spot, making it 4 in deep. Give it smoothed vertical sides except for one which should be sloped towards the parent plant. Smoothed vertical sides will help any shoots to grow vertically and so produce a manageable plant.
Place the tip in the deepest part of the trench and pin it down with a heavy wire staple. Replace the soil, firm and water.
In about three weeks, shoots should appear above ground level.
In September cut back the original stem at the crown of the parent plant, so that the layer can establish as an independent plant.
Cut off the rest of the original stem and shorten the growing tip before lifting the rooted layer in autumn after leaf-fall. Replant the layer immediately and label it.
Protect any layers that cannot be replanted straight away by wrapping their roots in damp newspaper, which is then placed in a plastic bag. Close the bag and tie the neck tightly so the roots will not dry out.
Propagation by tip-layering in this way can be repeated each year.
4 Pull down a stem. Dig a trench 4 in deep where its tip touches the ground.
5 Place the tip in the deepest part of the trench. Pin it down with a staple.
6 Replace the soil, firm and water, using a can with a coarse rose.
4 Pull down a stem. Dig a trench 4 in deep where its tip touches the ground.
10 Lift the layer very carefully to avoid damaging its fine, fibrous roots.
11 Plant the rooted layer at once in well-cultivated soil. Label it clearly.
12 Place layers that cannot be planted at once in damp newspaper in a plastic bag.
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