How to Care for a Citronella Plant: Complete Guide

By David Wilson · April 19, 2025

A citronella plant, often called citrosa geranium or Pelargonium citrosum, thrives with proper sunlight, well-draining soil, and moderate watering. To care for a citronella plant, provide 4–6 hours of direct sunlight daily, water when the top inch of soil is dry, and grow in a pot with drainage holes to prevent root rot. Regular pruning promotes bushiness, while indoor overwintering protects it from cold. These plants offer a lemony scent that may deter mosquitoes, though scientific evidence on repellency is limited.

Understanding the Citronella Plant

The citronella plant (Pelargonium citrosum) is commonly mistaken for a natural mosquito-repelling powerhouse. In reality, it's a scented geranium bred for its citrus-like aroma. While it emits a lemony fragrance when touched, actual mosquito deterrence requires crushed leaves and high concentration — making its effectiveness modest compared to commercial repellents.

Common Misconceptions

Citronella plants do not actively repel mosquitoes just by being nearby.
The oil used in candles and sprays comes from Cymbopogon nardus, a true citronella grass, not this geranium.
Labeling confusion has led many gardeners to expect more pest protection than the plant delivers.

Sunlight Requirements for Optimal Growth

Citronella plants need bright light to maintain compact growth and strong scent production. Insufficient light leads to leggy stems and weak fragrance.

Outdoor placement: South or west-facing locations with morning sun and afternoon partial shade in hot climates.
Indoor lighting: A sunny windowsill (south-facing preferred) or supplemental grow lights (14–16 hours/day).
Minimum exposure: At least 4 hours of direct sunlight daily; less results in poor vigor.

Watering Practices to Prevent Root Rot

Overwatering is the leading cause of death in citronella plants. They prefer slightly dry conditions between waterings.

Best Watering Guidelines

Check soil moisture: Water only when the top 1 inch (2.5 cm) feels dry.
Use pots with drainage holes to avoid water accumulation.
Reduce frequency in winter when growth slows.
Avoid wetting foliage to reduce fungal risk.

Soil and Container Selection

Well-draining soil is critical. Heavy, moisture-retentive soils promote root rot.

Soil Component	Purpose	Recommended Ratio
Potting soil (peat-based)	Base medium	50%
Perlite	Improves aeration and drainage	30%
Coarse sand	Prevents compaction	20%

Table data source:RHS Growing Guide, University of Minnesota Extension

This soil mix ensures rapid drainage while retaining enough moisture for healthy root function. The addition of perlite and sand prevents waterlogging, which is crucial for container-grown citronella plants.

Fertilizing Schedule and Nutrient Needs

Citronella plants are light feeders. Over-fertilization causes excessive leaf growth with reduced scent.

Fertilize every 4–6 weeks during spring and summer with a balanced, water-soluble fertilizer (e.g., 10-10-10) at half strength.
Withhold fertilizer in fall and winter.
Yellowing leaves may indicate nutrient deficiency or overwatering — assess soil moisture first.

Pruning and Maintenance Tips

Regular pruning keeps the plant bushy and prevents legginess.

Pinch back stem tips regularly to encourage branching.
Remove yellow or damaged leaves promptly.
Cut back by one-third in early spring to rejuvenate growth.
Always use clean, sharp scissors or pruners to prevent disease spread.

Winter Care and Indoor Transition

Citronella plants are tender perennials (USDA zones 9–11). In colder regions, bring them indoors before temperatures drop below 50°F (10°C).

Acclimate gradually: Move indoors over 7–10 days to reduce shock.
Place near a bright window and monitor for pests like spider mites.
Reduce watering frequency during dormancy.
Avoid drafty areas or heat vents.

Propagation: How to Grow New Plants

Propagate via stem cuttings for identical clones.

Take a 4–6 inch cutting from a healthy stem.
Remove lower leaves and dip in rooting hormone (optional).
Plant in moist potting mix and cover with a plastic bag for humidity.
Place in bright, indirect light; roots form in 3–4 weeks.

Frequently Asked Questions About Citronella Plant Care

Does a citronella plant really repel mosquitoes?

No, simply having a citronella plant nearby does not effectively repel mosquitoes. The plant must be crushed or rubbed to release oils, and even then, its effect is minimal compared to DEET or picaridin-based repellents. Studies show that Pelargonium citrosum lacks sufficient citronellal content for reliable protection.

How often should I water my citronella plant?

Water when the top inch of soil is dry, typically once every 7–10 days in summer and less frequently in winter. Always ensure the pot drains well to avoid root rot.

Can I grow citronella plants outdoors year-round?

Only in USDA zones 9–11. In colder zones, grow in containers and bring indoors before frost. Extended exposure to temperatures below 50°F (10°C) can damage or kill the plant.

Why are my citronella plant's leaves turning yellow?

Yellow leaves usually indicate overwatering or poor drainage. Check soil moisture and ensure the pot has drainage holes. Low light or nutrient deficiency can also contribute, but overwatering is the most common cause.

Do citronella plants need full sun?

They thrive in full sun (4–6 hours of direct sunlight daily) but tolerate partial shade. Too little light causes leggy growth and weak scent. Indoors, place in the brightest window available.