Take a non-flowering shoot, cut just below a node, strip the lower leaves and put it straight into gritty compost. Geraniums root easily and do not need hormone.
A note on the name
What gardeners call geraniums are almost always pelargoniums. True hardy geraniums are a different genus and are usually propagated by division rather than cuttings. The instructions here are for pelargoniums, which are the tender bedding and container plants with the rounded scalloped leaves.
Taking the cutting
- Choose a healthy shoot without flower buds. Flowering shoots divert energy into blooming rather than rooting.
- Cut a length of about ten centimetres, making the cut just below a leaf node with a clean blade.
- Remove the lower leaves so the bottom third of the stem is bare, and pinch out any buds.
- Leave the cutting on a windowsill for a few hours so the cut surface dries slightly. This step is specific to pelargoniums and it noticeably reduces rot.
- Insert into gritty compost, around a third of the stem below the surface, firming gently.
Several cuttings around the edge of one pot works better than one per pot, because the pot edge provides warmth and drainage where roots form fastest.
Aftercare while they root
Keep them somewhere bright but out of direct midday sun, and water sparingly. The instinct to cover cuttings with a plastic bag is wrong here. Pelargonium stems are semi-succulent and trap humidity leads directly to rot, which is the opposite of the advice for most softwood cuttings.
Rooting normally takes two to four weeks. The reliable sign is new growth at the tip, not resistance when tugged, since resistance can simply be the stem swelling.
Potting on and overwintering
Once rooted, pot into individual containers of ordinary potting compost. If the cuttings were taken in late summer, keep them frost free over winter somewhere bright and water only enough to stop them shrivelling. They will look sparse by February, which is expected. Cut them back in early spring and they will bush out for the season.
Why cuttings fail
- Too much water. The commonest cause by a wide margin.
- Covered with plastic. Right for many cuttings, wrong for these.
- Flowering shoot chosen. Roots much more slowly, if at all.
- Cut between nodes. Roots form at nodes, so a stem cut mid-internode has less to work with.