Pelargoniums, the plants most people call geraniums, are among the easiest garden plants to multiply, and a single healthy plant can supply a windowsill full of new ones. Cuttings give an exact copy of the parent, while seed works for some types and can produce varied plants. For cuttings, the biggest danger is not failure to root but rot, which is why being clean and careful with water matters as much as technique.
Cuttings or Seed, Which Should You Choose
A rooted cutting carries the same genes as its parent, so a cutting from a seed-grown geranium is still that same seed variety.1Crocker Nurseries. What is the difference between Zonal and Seed Geraniums? That makes cuttings the way to keep a favourite colour, a scented-leaf plant or a trailing ivy geranium true. Until 1962 geraniums could only be grown from cuttings; seed-raised types came later.2Juniper Station. A Small History: Geraniums Cutting-grown types also tend to have larger flowers and are sometimes hardier than seed-raised ones.3Juniper Station. A Small History: Geraniums
Bedding zonal F1 and F2 types and species such as apple-scented Pelargonium odoratissimum can be grown from seed.4RHS Growing Guide. How to grow pelargoniums Seed from a fancy named regal or variegated plant is unlikely to grow into a copy of its parent. Most named regals, variegated types and scented-leaf plants are hybrids or selected forms, so their seedlings shuffle the parents’ genes and come out varied.
Your situation usually settles the choice. To save a patio plant before frost, take cuttings in late summer. If you want dozens of cheap bedding plants for borders, buy F1 seed. Cuttings also flower sooner because they skip the seedling stage.
A single parent plant can give a handful of cuttings at no cost. Seed becomes the cheaper route only when you want many plants of one bedding type, since a packet gives far more plants than a parent can supply cuttings. Seed does need warmth and a long head start in late winter.
When and How to Take a Pelargonium Cutting
Softwood cuttings, the soft green tips of shoots, can be taken from spring to autumn.5RHS Growing Guide. How to grow pelargoniums Late summer is a good time, and the old woody plants can then be discarded at the end of the season.6RHS Growing Guide. How to grow pelargoniums
Tip cuttings root far better than pieces from lower down the stem. In rose-scented geranium, about 70% of tip cuttings rooted against about 37% of cuttings from the base of the shoot.7Indian Journal of Agricultural Research. Effect of time of planting, type of cutting and plant growth regulators on rooting in Pelargonium graveolens L. Herit Use the top few inches of each stem and skip the old woody lower part. Pick sturdy, short-jointed shoots rather than thin, drawn-out ones, which are weak and slow to establish.
The parent plant matters too. Plants grown in brighter light give cuttings with more stored sugar at the base, which supports more roots.8Plant Science. Interplay between initial carbohydrate availability, current photosynthesis, and adventitious root formation in Pelargonium cuttings Very lush, heavily fed parents can give cuttings that root less well, as seen in zonal geraniums.9MDPI Agronomy. Advancing Sustainability in Pelargonium Nursery Management: Scientific Exploration of an Innovative Prolonged Cold Storage System for Cuttings Take cuttings from a sunny plant that has not been pushed with lots of nitrogen feed.
Choose a healthy, non-flowering shoot about 7 to 10 cm long from the end of a stem, with fresh green growth and no spots or wilting. Use a clean, sharp knife and cut just below a leaf joint (node), where the stem roots most readily. Strip the lower leaves and any flower buds, leaving two or three leaves, so the cutting puts its energy into roots rather than flowers. Set it into the mix promptly; you don’t need to leave the cut end drying for days. Taking a few cuttings from different stems spreads the loss, so the parent keeps its shape and still flowers.
Many cutting guides tell you to cover cuttings with a plastic bag to hold humidity. Pelargoniums have fleshy stems that rot in a humid, enclosed space, so leave them uncovered on a bright windowsill out of hot direct sun. Bright indirect light is enough. Cooler air during rooting kept more sugar in the cuttings, which meant fewer yellowing leaves, better survival and more roots.10Postharvest Biology and Technology. Response of post-storage carbohydrate levels in pelargonium cuttings to reduced air temperature during rooting and the relationship with leaf senescence and adventitious root formation If the mix dries out, water it lightly rather than trying to boost humidity.
What to Root Pelargonium Cuttings In
Perlite alone gave the heaviest roots and new leaves in rose-scented geranium cuttings, and a peat and perlite mix produced as many roots and leaves.11Elsevier / Scientia Horticulturae. Quality of *Pelargonium graveolens* cuttings as affected by the rooting medium Garden soil gave the poorest roots, and peat alone held back new leaves.12Elsevier / Scientia Horticulturae. Quality of *Pelargonium graveolens* cuttings as affected by the rooting medium Use a sterile seed-and-cutting mix lightened with plenty of perlite, never garden soil.
Rooting hormone (IBA) is the active ingredient in many rooting powders, and it gave ivy geranium cuttings roots about 29% longer and 57% heavier.13Revista de Ciencias AgrÃcolas. Enhancing Pelargonium peltatum Propagation in the Azores: Role of Cutting Type and Indole-3-Butyric Acid Still, pelargoniums root readily without help, so rooting powder is a useful extra, not a necessity.
If you use it, pour a little into a separate dish rather than dipping into the tub, so any disease on a cutting doesn’t contaminate the whole supply. Dip only the cut end and tap off the excess, because a thick coating can hold moisture and doesn’t help. Make a hole in the mix with a pencil first, so the powder isn’t rubbed off as you push the cutting in.
Water once after potting, then only when the mix is nearly dry, since constantly wet mix invites rot. New leaf growth at the top often suggests roots have formed below, though it isn’t proof on its own. To check, tug a cutting very gently: resistance means roots, whereas one that slides out has not rooted yet. Pot on into general compost once the cutting is well rooted.
Why Cuttings Rot and How to Prevent It
Blackleg, or black stem rot, starts at the cut end as a brown, water-soaked rot that climbs the stem and turns coal black.14Pacific Northwest Pest Management Handbooks. Geranium (Pelargonium spp.)-Blackleg and Damping-off Leaves then wilt and the cutting dies.15Pacific Northwest Pest Management Handbooks. Geranium (Pelargonium spp.)-Blackleg and Damping-off It is hard to stop once begun.16Pacific Northwest Pest Management Handbooks. Geranium (Pelargonium spp.)-Blackleg and Damping-off
Use healthy, disease-free material and a sterile soilless mix.17Pacific Northwest Pest Management Handbooks. Geranium (Pelargonium spp.)-Blackleg and Damping-off Clean and disinfect knives often, avoid overwatering and keep hose ends off the ground.18Pacific Northwest Pest Management Handbooks. Geranium (Pelargonium spp.)-Blackleg and Damping-off At home, that means wiping blades with rubbing alcohol between plants, so a disease carried on the blade isn’t passed from one cutting to the next. Wash reused pots in hot soapy water to remove old compost and the organisms that survive in it, and use fresh bagged mix each time, as reused mix can harbour rot organisms.
Water the mix rather than the cuttings, and let the surface dry between waterings. Pots need drainage holes, because a pot standing in a saucer of water keeps the base of the cutting wet. Giving each cutting some space helps air move around the leaves and lets them dry.
Check your cuttings every couple of days for darkening at the base of the stem, where black stem rot begins. If one has blackened, remove it at once along with the mix around it, so the rot doesn’t reach its neighbours. A limp cutting needs different handling depending on the mix: if the mix is dry, it needs water, but if the mix is wet, it is likely rotting and watering will make it worse.
Bacterial blight shows as small water spots under leaves that become sunken dead spots, wedge-shaped wilting, and stems that blacken and shrivel.19Cooperative Extension Service, University of Connecticut. How to Propagate Pelargoniums from Cuttings and Seeds There is no chemical cure, so remove infected plants immediately.20Cooperative Extension Service, University of Connecticut. How to Propagate Pelargoniums from Cuttings and Seeds Water at soil level and keep leaves dry; warm nights above 71°F (22°C) and whiteflies favour spread.21Cooperative Extension Service, University of Connecticut. How to Propagate Pelargoniums from Cuttings and Seeds
How to Grow Pelargoniums From Seed
Sow in late winter and grow on somewhere warm and protected, such as a heated greenhouse.22RHS Growing Guide. How to grow pelargoniums Keep the seed shaded at 21 to 24°C, with the warmer end preferred.23geraniaceae-group.org. How to Propagate Pelargoniums from Cuttings and Seeds
Fill a tray or pots with moist seed compost, firm it lightly and level the surface. Press the seeds in just under a thin layer of compost or vermiculite rather than burying them deeply. Cover the tray to hold moisture and keep warm, for instance with a propagator lid, and keep the compost damp but not soaking. Uncover and move the tray to bright light as soon as seedlings appear, so they don’t become tall and weak.
Many pelargonium seeds have a hard coat that blocks water, and dry storage does not soften it.24Seed Science Research. Physical dormancy in Geraniaceae seeds Hardness varies a lot between species, so some seed sprouts readily and some sits for months.25Environmental Control in Biology. Effect of Treatment with Concentrated Sulfuric Acid and a Homogenizer, and Temperature at Germination and Storage on Seed Germination in Eight Pelargonium Species Gently rubbing hard species seed on fine sandpaper lets water in.
Bought bedding seed is usually ready to sow without treatment, so you can simply follow the packet. Species seed is more likely to need nicking or rubbing because its coat tends to be harder, and it may still be slow to come up.
Caring for New Plants and Overwintering Cuttings
If you can’t pot cuttings at once, a short spell bagged in the fridge is possible. Unrooted zonal cuttings kept in sealed bags at 4°C under dim light still rooted over 50% of the time after nine weeks.26Journal of Horticultural Science. Storage of cuttings of Pelargonium × hortorum Bailey Ivy geranium cuttings tolerate cold storage of up to four weeks better than zonals.27Agronomy. Advancing Sustainability in Pelargonium Nursery Management: Scientific Exploration of an Innovative Prolonged Cold Storage System for Cuttings
Feed young plants moderately rather than heavily, as excessive feeding encourages disease.28Pacific Northwest Pest Management Handbooks. Geranium (Pelargonium spp.)-Blackleg and Damping-off Keep rooted cuttings on a bright, cool windowsill, since warm dim rooms make them leggy. Water sparingly in winter, letting the compost dry out a little between waterings, as wet cold compost invites rot. Pinch out the growing tips in spring to encourage bushier plants with more flowering shoots, and pot up into a slightly larger pot as the roots fill the current one.
Pelargoniums are frost-tender and should go outdoors only after the last frost. Plants raised indoors need a week or so to adjust, so set them outside for a few hours a day at first and lengthen the time. Bring them in if a cold night is forecast. Move them to full sun gradually, as leaves grown indoors can scorch in strong direct sun.