The perennials used in summer bedding displays are not frost hardy and most are propagated each year from cuttings. Although you can lift plants in autumn, cut them back and keep them under glass over winter, their subsequent performance will be poor when compared with young plants raised from cuttings.
When you take cuttings, always remember:
- To take them early in the day, when plants are turgid. Prepare and insert the cuttings immediately, otherwise place in water or a polythene bag and keep in the shade.
- After inserting them in cuttings compost, water in well using a fine rose.
- Once they have rooted harden them off gradually, then pot up singly in John Innes No 1 or a proprietary loam-less cuttings compost. Cuttings compost is often called seed and cuttings compost. Cuttings are rooted in cuttings compost, but are then potted up into multi-purpose compost once established.
Spring: Softwood cuttings
Examples: Heliotrope, ivy-leaved pelargoniums.
These cuttings are capable of very rapid root development given suitable growing conditions. Keep stock plants under glass and prune them back in winter. New shoots will grow vigorously in warm spring conditions and these provide cuttings. (Dahlia tubers are started into growth in late winter for the same purpose).
Take cuttings of about 10cm (4in) in length, cutting below a leaf joint, or node; shorter side shoots are taken with a ‘heel’, where the sideshoot is pulled away from the parent shoot with a sliver of bark attached. Trim the tail of the heel to tidy it up. Remove leaves from the lower third of the stem and insert in cuttings compost to the base of the leaves, spacing cuttings so the leaves do not touch. Then place under mist or in a closed propagator with bottom heat ideally 21-24ºC (70-75ºF).
Early Summer: Greenwood cuttings
Examples: Fuchsias, Zonal pelargonium (bedding geraniums)
These are cuttings of the tips of young growths taken from about the beginning of June when young growth is slowing. They are firmer and more mature than softwood cuttings, and rooting is slower. Take shoots 7.5-10cm (3-4in) long; smaller ones can be used if material is limited. Cut below a leaf joint, or node, remove the leaves from the lower half and dip the base in a softwood hormone rooting preparation. Insert in a mist unit, under a polythene tent or in a container of cuttings compost placed in a closed frame.
Late Summer : Semi-ripe cuttings
Examples: Argyranthemum, Senecio maritima.
These are taken in July and August when growth is slowing and stems are becoming firm. Take cuttings from main stems or use strong, leafy non-flowering side shoots from the main stems. Remove the tips if soft; otherwise leave intact. Length of cuttings can vary from 10-15cm (4-6in) depending on the vigour of the plant being propagated.
Remove leaves from the lower 5cm (2in) and dip the base in a hormone rooting preparation. Then insert about 2.5cm (1in) deep in well-drained pots in a clear polythene bag or in a covered propagating case. Place pots or case in a cool greenhouse and shade from bright sunlight.
Step by step to propagating Pelargonium
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1. Take semi-ripe cuttings in late summer from strong, leafy, but ideally non-flowering sideshoots between 5-15cm (2-6in) long. |
2. Trim below a leaf joint (node), and cut off the foliage from the lower half. Apply a hormone rooting formulation to the base. |
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3. Insert cuttings up to the lowest leaf in individual or larger pots containing a proprietory cuttings compost and water well. |
4. Cover with a clear polythene bag or put in a propagator. New top growth indicates rooting; at this point pot up plants individually. |
Further information
Search for suppliers of your favourite plants in the online RHS Plant Finder
The International Plant Propagators Society