Gadenin日本語Get the appThe plant wants to root; your job is to stay out of the way
Geranium cuttings are the easiest thing most gardeners will ever propagate, and the failures almost all come from treating them like difficult ones. The standard cutting routine of a sealed propagator, a plastic bag over the pot, misting and constantly moist compost is the exact set of conditions in which a geranium cutting rots at the base before it can root.
The reason is the plant's own construction. Those thick jointed stems carry enough stored water to keep a detached cutting turgid for a fortnight with no roots at all, so it does not need humidity to survive the wait. What it needs is enough air at the cut end to callus over instead of turning to mush.
So the whole method is subtraction. Gritty free draining compost, no cover, no misting, bright light out of direct scorching sun, and almost no water. Done that way, cuttings taken in the growing season root in two to three weeks and eight or nine out of ten take. Done the conventional way, most of them go black at the base.
- Choose the right shoot Take a non flowering shoot tip three to four inches (8 to 10 cm) long from firm current season growth. Avoid soft floppy tips and avoid old woody stems, which are slow and unreliable.
- Cut just below a leaf joint Use a clean sharp blade and cut straight across immediately below a node, because that is where roots emerge. Then strip off the lower leaves so only the top two or three remain, and remove any flower bud or stalk entirely.
- Let the cut end dry first Lay the cuttings on newspaper somewhere shaded and airy for a few hours, or overnight, until the cut face is dry and sealed to the touch. This one step is what prevents blackleg, and it is the step everyone skips.
- Insert into gritty potting mix Fill small pots with potting mix mixed with a third grit or perlite. Push each cutting in around an inch (2.5 cm) deep, right against the side of the pot where drainage is best, and firm lightly. Rooting hormone is unnecessary.
- Water once, then leave alone Give one light watering to settle the compost, then let it dry out and keep it barely moist. Stand the pot uncovered in good light at 60 to 70F (15 to 21C). Do not cover, do not mist, do not stand in a saucer.
Several cuttings around the edge of one small pot root more reliably than one cutting in the middle of a pot, because the compost dries faster and the cuttings support each other.
Knowing when they have rooted
Do not pull cuttings up to look. The clear signal is new growth: the tip extends and produces a new leaf that is a fresher green than the rest. That happens at two to three weeks in warm conditions and takes four to six weeks in autumn as light and warmth fall away.
A rooted cutting also feels anchored. Grip the base of the stem and press gently sideways, and a rooted one resists while an unrooted one moves freely in the compost. Roots showing at the drainage hole is the final confirmation.
Pot each rooted cutting on individually into a three and a half inch (9 cm) pot of the same gritty mix. Give no feed for the first six weeks, then a half strength liquid feed every two or three weeks. Pinch the growing tip out once the plant has five or six leaves to make it branch.
| Timing of cutting | Weeks to root | What it is for |
|---|---|---|
| Spring, from an overwintered plant | 2 to 3 | Plants that flower the same summer |
| Early summer, from soft tips | 2 | Filling gaps and extra containers |
| Late summer to early autumn | 3 to 4 | The main batch, to overwinter as small plants |
| Late autumn, indoors | 5 to 6 | Possible but slow; keep drier still |
| Midwinter | Not worth it | Too little light; wait for spring |
Late summer cuttings are the insurance policy
The most useful batch of the year is taken in late summer or very early autumn, while there is still warmth and light. Small plants rooted then come through winter far better than big old plants do, because they take almost no space on a windowsill and have no woody base to rot.
Take three or four cuttings from every plant you would be sorry to lose. If the parent then dies in a wet winter or fails to come through dormancy, nothing is actually lost. This is why the plant has been passed hand to hand between gardeners for generations, and why any geranium you admire is worth asking for a shoot of.
Keep the young plants cool, bright and dry over winter, at around 45 to 55F (7 to 13C), and water only enough to stop them shriveling. Pinch them once in late winter as light returns and they will be branched plants ready to go out after the frosts.
Label every cutting with the parent plant and the date it was taken. By spring one pot of unlabelled cuttings looks exactly like another, and the flower color is the one thing you cannot tell from the foliage.
Seed and division
Bedding geraniums can be raised from seed, but it is a long job and rarely worth it for a home grower. Seed needs sowing about twelve to fourteen weeks before planting out, at a steady 70 to 75F (21 to 24C), and the seedlings need strong light throughout. Cuttings give a flowering plant far sooner and give you an exact copy of the plant you liked.
Seed saved from your own plants will not come true. Almost everything grown as bedding is a hybrid, and its offspring vary in color, height and habit. It can be a pleasant experiment but it will not reproduce the parent.
Division is not a technique for this plant. It grows from a single main stem rather than a clump, and attempts to split it usually kill both halves. If a plant has become a bare woody trunk with growth only at the top, do not try to divide it: take the tops as cuttings and start again with young plants.