Geranium
Pelargonium × hortorum
Garden geraniums are bushy plants with rounded, often zoned leaves and bold clusters of red, pink, white or salmon flowers. They are classic balcony and window-box plants and flower for months in sun.
Photo: Dittaeva (Wikimedia Commons) · CC BY-SA 3.0, via Wikimedia Commons
Essential Care Requirements
Light
Full sun
Watering
Low
Water when the top of the soil is dry. Geraniums dislike wet roots, especially in the monsoon.
Soil
Well-drained potting mix with perlite; pH 6.0–7.0.
Temperature and humidity
5–32 °C · Low humidity
Feeding
Feed every two weeks with a potassium-rich liquid fertilizer while flowering.
Pruning and propagation
Propagate by stem cuttings, seed
Deadhead regularly and cut back leggy plants by half in spring.
Geraniums can cause vomiting and skin irritation in cats and dogs.
Top Cultivation Tips
Take cuttings in autumn for next season.
Let cuttings dry for a few hours before planting.
Keep under cover during heavy rain.
Scented-leaf types make good kitchen plants.
Common problems
Bacterial blight
A bacterial disease that causes water-soaked angular leaf spots and dark spots on pods and fruit in beans, pomegranate, geranium and other plants.
How to treat it →DiseaseFrost damage
Injury caused when ice forms inside plant tissue, turning leaves, flowers and shoots black, limp or papery after a cold night.
How to treat it →DiseaseGrey mould
A fungal rot that covers flowers, fruit and soft stems with fuzzy grey mould in cool, damp conditions.
How to treat it →DiseaseOedema
Small blisters and corky bumps on leaf undersides, caused when roots take up water faster than the leaves can release it.
How to treat it →DiseasePythium root rot
A water mould that attacks fine roots in wet, poorly drained or warm stagnant conditions, causing wilting and stunted plants.
How to treat it →DiseaseRoot rot
Roots decay in waterlogged soil, so the plant wilts and yellows even though the soil is wet.
How to treat it →PestWhiteflies
Small white flying insects that gather under leaves, sucking sap, spreading viruses and leaving sticky honeydew.
How to treat it →DiseaseWilting plants
Leaves and stems that droop, caused by too little water, too much water, heat or root and stem diseases.
How to treat it →
