Pelargonium citronellum (Citronella geranium) care

Light

Pelargonium citronellum needs sun on the leaves, not just bright ambient room light. Full sun, ideally 6 or more hours, for compact growth and the strongest citrus scent. The brightest indoor window in winter; low light makes it sparse and stretched. A south or west-facing windowsill in the northern hemisphere is the default; anywhere else, expect the plant to stretch and pale out within a season.

Watering

Water pelargonium citronellum when the top 3-4 cm of soil is dry, roughly every 7-10 days. The actual day count varies with pot size, light, and season — the finger test (or lifting the pot to feel its weight) is more reliable than a fixed calendar. Empty any drainage saucer afterwards so the pot isn't sitting in water. Water deeply then allow to dry well between drinks. This vigorous species is quite drought-tolerant once established and resents constantly wet roots; reduce watering in winter.

Soil and pot

Pelargonium citronellum grows best in free-draining loam or potting mix with added grit or perlite. Gritty, sharply drained peat-free compost. Tolerates poorer, leaner soils; neutral to slightly alkaline pH is ideal. Avoid heavy, moisture-retentive mixes. A pot with a working drainage hole is non-negotiable for this species — even free-draining mix will turn soggy in a closed planter. If you love the look of a decorative pot without a hole, use it as a cachepot around an inner nursery pot you can lift out to water.

Humidity and temperature

Pelargonium citronellum sits happiest at around 30-50% humidity and 10-25°C (50-77°F). Prefers dry to average air with good airflow. It is undemanding on humidity, and damp, stagnant conditions only encourage fungal leaf problems; do not mist. If you keep the room above 10 year-round and avoid placing the plant near a cold draught, a hot radiator, or an air-conditioning vent, you have already handled the two biggest indoor stressors.

Fertilising

Feed pelargonium citronellum sparingly. Feed every 3-4 weeks in spring and summer with a balanced or high-potash liquid feed; this vigorous grower needs only moderate nitrogen. Suspend feeding in autumn and winter. Skip fertiliser entirely on a stressed, recently-repotted, or actively wilting plant — fertiliser salts make damage worse, not better. Wait for a round of healthy new growth before resuming a feeding rhythm.

Common problems

Below are the issues we see most often on pelargonium citronellum in the Growli community. Each is annotated with the most common cause so you know where to start.

• Tall and leggy — Its natural vigour makes it sprawl if unchecked; prune and pinch in spring to maintain a bushy, well-branched shape.
• Mistaken pest-repellent claims — The 'mosquito plant' name overpromises; crushed leaves smell of citronella but the growing plant does not meaningfully repel mosquitoes. Manage expectations rather than relying on it.
• Woody, bare base — Old plants lose lower leaves and turn woody; prune hard in early spring or restart from cuttings to rejuvenate.
• Rust and grey mould — Damp, crowded conditions invite fungal disease. Improve spacing and airflow and remove infected foliage promptly.

Propagation

Roots readily from 8-12 cm semi-ripe stem cuttings in spring or summer; let cuts callus, insert into gritty compost, keep just-moist and warm, and roots form in roughly 3-4 weeks. Propagation is the cheapest, most satisfying way to expand a collection — and it doubles as insurance against losing a mature plant to an accident. Take a backup cutting once the parent is established and healthy.

Toxicity to pets

Pelargonium citronellum is toxic to pets. The ASPCA lists Geranium / Scented Geranium (Pelargonium spp.) as toxic to cats, dogs and horses. Toxic principles are geraniol and linalool; signs include vomiting, anorexia, depression and dermatitis, with cats most sensitive. Keep this plant away from pets. If you keep cats, dogs, or curious children in the house, weigh placement carefully — a high shelf or a hanging planter is enough for casual safety. For severe ingestion incidents, call your local vet and the ASPCA Animal Poison Control Center (in the US, 888-426-4435).

Pet-safety status is sourced from the ASPCA Toxic and Non-Toxic Plant List, which catalogues the most-asked-about plants for cats, dogs, and horses.

Pelargonium citronellum deep-dive guides

Every aspect of pelargonium citronellum care, each with its own calibrated guide:

• Pelargonium citronellum watering schedule
• Pelargonium citronellum light requirements
• Best soil mix for pelargonium citronellum
• Pelargonium citronellum fertilizing guide
• When to repot pelargonium citronellum
• How to propagate pelargonium citronellum
• Pelargonium citronellum growth rate & size
• Pelargonium citronellum cold hardiness
• Pelargonium citronellum temperature & humidity
• Is pelargonium citronellum toxic to cats & dogs?
• Is pelargonium citronellum toxic to cats?
• Is pelargonium citronellum toxic to dogs?

Featured in these plant shortlists

Pelargonium citronellum qualifies for 1 curated Growli shortlist — each one filtered objectively from our structured plant-care library, so the selection is consistent and checkable:

• Best fragrant houseplants — Indoor plants with scented flowers or aromatic foliage — greenery you can smell, selected from our care library.
• Browse all 29 plant shortlists — pet-safe, low-light, drought-tolerant and more

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Pelargonium citronellum is also known as Citronella geranium, Mosquito plant, and Lemon pelargonium.

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