Pelargonium (geranium)

Pelargonium spp. · Geraniaceae

Water-wise colour for pots.

Photo: Krzysztof Golik, CC BY-SA 4.0, via Wikimedia Commons

Sun: Full sun.
Soil: Free-draining; dislikes soggy soil. Add gypsum to clay.
Soil pH: Neutral to slightly alkaline.
Water: Low. Water sparingly; drought-tolerant once established. Avoid overhead watering.
Hardiness: Most Australian climates except those with extreme or heavy frosts; tolerates light frost.
Height and spread: Varies by type: upright zonal and regal types about 30-60 cm; ivy-leaf types trail.

Guv's tipPelargoniums are easy from stem tip cuttings, about 10 cm with the lower leaves removed. Water sparingly and avoid overhead watering.

Through the year

When to plant

Spring, once frost risk has passed (garden planting from August).

Harvest or flowering

Spring through summer; can flower almost year-round in mild areas.

Pruning

Deadhead and trim lightly through flowering. Cut back by about a third (up to two-thirds) at the end of summer or in autumn.

Making more plants

Stem tip cuttings (very easy; about 10 cm, lower leaves removed); seed.

Watch out for

Pest

Caterpillars

Look for: Chewed leaves; small, well-camouflaged green caterpillars.

What to do: Hand-pick; pyrethrum spray.

Disease

Grey mould (Botrytis blight)

Botrytis cinerea

Look for: Grey fuzzy rot on flowers and leaves.

What to do: Remove dead material, avoid overhead watering, and improve airflow.

Always read and follow the label on any treatment, and check it is approved for use where you live.

Safety and spread

Pets and people: Toxic to dogs, cats and horses (ASPCA: geraniol, linalool), causing vomiting, loss of appetite, depression and dermatitis. A low-severity poison; cats are most sensitive.

Weed risk: Common garden pelargoniums are not listed as weeds. Pelargonium alchemilloides ('garden geranium') is an escaped environmental weed naturalised in south-west WA, and is regulated in NSW only under the general biosecurity duty.

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