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!