Pelargonium grandiflorum can be propagated from seed and cuttings. Stem cuttings, 15 cm long selected from healthy vigorous plants can be taken at any time of the year. This is also the most commonly used method of propagating pelargoniums. Plants grown through this method will flower within 3 to 6 months. A rooting hormone will accelerate and improve rooting success. Place the cuttings in a propagation tray, containing separate compartments or plugs with river sand and place in cold frames or well lit area and keep them moist, not saturated. The cuttings should root in 3 weeks. Give the rooted cuttings a 3 week weaning period and transplant them into a well-drained potting soil mix and place them in a shady position.

Sow seeds in late summer to early autumn. The seed should be sown in a light, well-drained soil mix. Sprinkle the seeds evenly in the seed tray and cover them with fine white silica sand or fine-milled pine bark. The seeds should be watered gently but thoroughly with a fine soft nozzle spray head or watering can. Place the sown seed in light shade with no direct sun. The seeds germinate in 3 weeks. Transplant into smaller half litre bags or 5cm pots when the seedlings have 3 pairs of leaves. Plants grown from seeds will flower within 12 to 18 months. Pelargoniums grow happily outdoors free of diseases, but if the same plant is grown indoors or in a greenhouse the warmer conditions and lack of air circulation usually result in pests such as aphids, white fly and mealy bug. They can also be susceptible to fungal diseases such as rust and powdery mildew. Please contact your local garden centre to ask for the appropriate pesticide and fungicide to treat these problems.