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division and layering
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RHS Level 2 Certificate
Week 14- vegetative reproduction by stem cuttings, layering and division.
Learning objectives
Review of leaf cuttings. 1.1 State the physiological factors to be fulfilled for successful
propagation by layering. 1.2 Describe how to propagate ONE NAMED plant for EACH of
the following types of layering: air; simple; and serpentine 1.3 Describe the aftercare required for plants raised by
layering. 1.4 State the conditions which have to be met to ensure
successful propagation by division. 1.5 Describe how to propagate by division ONE NAMED plant
of EACH of the following types: a suckering shrub; a fibrous-rooted perennial; a perennial with distinct buds (eyes).
1.6 Describe the aftercare of plants propagated by division.
Christmas Prize Quiz
Test conditions 30 minutes Ho! Ho! Ho!
Leaf cuttings
Leaf lamina – entire leaf; veins cut across (shallowly) on the back of the leaf. Pinned down on compost. Begonia rex
Midrib – Leaf detached and central vein removed; cut edge inserted into shallow trench in compost and firmed. Streptocarpus rexii
Petiole – entire leaf, petiole inserted into compost so base touches. Saintpaulia ionantha
Leaf section – squares (planted to 1/3 of height in tray) or chevrons (the pointy end is the ‘bottom’)
Plantlets form where the cut leaf veins touch the compost.
Propagation by division
Used for perennials – clump forming, suckering and rhizomes.
Use more juvenile offsets from the edge of the clump or plant.
Divide summer flowering plants in the spring or autumn e.g, Iris ensata
Divide spring flowering plants in the summer after flowering e.g. Epimedium x rubrum
Aftercare – weed to reduce competition, do not allow soil to dry out.
Plants that can be divided
Iris ensata (or any rhizomatous iris)Epimedium x rubrum Bergenia purpurescensHosta sieboldianaPhyllostachys nigraSarcoccoa hookerianaNote: Three of these are monocots – monocots cannot generally be propagated by cuttings.
Propagation by layering
Simple layering – advantages: can be used to propagate hard to root plants; needs little equipment; no hardening off
Disadvantages – produces relatively few plants and is slow.
Propagation by layering
Serpentine layering -Used for woody climbers e.g, Lonicera. Produces several plants per stem however it needs quite a lot of space.
Air Layering – used for plants with rigid stems e.g. Magnolia grandiflora
Aftercare for layered plants
Keep soil moist (sphagnum moss in air layering) until rooting occurs.
Once rooted (and shoots are produced in serpentine layering) detach from the parent plant and move to final position or into a pot to grow on. Remove any residual stem from the parent plant without leaving a snag.
Health and safety
The scalpels are very sharp. Take care when cutting.
Some people are allergic to the sap of some plants – use the latex gloves if you are or may be affected.
Do not get the rooting powder on your skin. Use the wet wipes if you do. Do not inhale the rooting powder – put the lid on when not in use.
Characteristics of plant material for propagation
True to type – must show the characteristics you want.
Healthy – no signs of virus, no obvious or severe infestation or infection.
Turgid – must be well watered and protected from dehydration after removal from parent.
Juvenile – the more juvenile the material the better it is likely to root.
Some hints
Do not touch the cut surfaces – the acids on your skin will inhibit rooting.
Use rooting powder sparingly. Remove unwanted leaves with the knife not by
tearing to avoid damage to the bark. Reduce any large leaves by half. Use the knife
or secateurs. Pinch out the tip of stem cuttings if soft or to
encourage branching growth.
Internodal cuttings
A cut is made about 2cm below the leaf node and another immediately above. The cutting is a short piece of stem with a leaf and the axillary bud. Several cuttings can be taken from a single length of stem.
No rooting powder is needed. The cuttings are inserted into a pot of cutting compost so that the axil is just visible above the compost.
Suitable for Hedera sp. Camelia sp. Clematis and other harder to root climbers.
Semi Ripe cuttings
Take above a node. 10cm long. Trim to below a node and remove leaves from bottom so 2-3 sets of leaves remain.
Wound the base by removing a sliver of bark. Dip into rooting powder – tap off excess
carefully Use dibber to make hole in prepared pot, insert
so the bottom leaves are just above the surface. Firm in.
Learning outcomes
Review of leaf cuttings. 1.1 State the physiological factors to be fulfilled for successful
propagation by layering. 1.2 Describe how to propagate ONE NAMED plant for EACH of
the following types of layering: air; simple; and serpentine 1.3 Describe the aftercare required for plants raised by
layering. 1.4 State the conditions which have to be met to ensure
successful propagation by division. 1.5 Describe how to propagate by division ONE NAMED plant
of EACH of the following types: a suckering shrub; a fibrous-rooted perennial; a perennial with distinct buds (eyes).
1.6 Describe the aftercare of plants propagated by division.
Term Dates
Classes start again on the 8th January
Happy homework!
HAPPY CHRISTMAS!
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