Citronella Grass (Nardus Grass) care

Light

Aim for at least 4-6 hours of direct sun on the leaves. Requires full sun for at least 6–8 hours daily. As a tropical grass native to open, sun-exposed environments, it performs best in the hottest, brightest position available. In shade, growth is weak, leaves lose their characteristic blue-green colouration, and essential-oil concentration drops significantly. If your only bright window faces south, that's perfect for citronella grass — same window any aroid would fry on.

Watering

Watering citronella grass: every 5–7 days; more frequently in containers in hot weather. The number that matters isn't the day of the week — it's how dry the top 2-3 cm of the pot feels. A finger in the soil tells you more than a watering app. After every watering, tip the saucer. Water deeply to encourage deep root growth, then allow the top few centimetres of soil to dry before rewatering. Established clumps tolerate short dry spells but perform best with consistent moisture during the growing season. Container-grown plants dry out faster than in-ground specimens and may need watering every 2–3 days in hot weather. Reduce watering significantly when overwintering indoors.

Soil and pot

Citronella Grass grows best in well-drained, moderately fertile loam or loam-sand mix. Grows in a broad range of soils (pH 5.5–7.5) provided drainage is adequate. Heavy clay that remains waterlogged causes root rot. Amend poor or clay soils with compost and horticultural grit. In containers, use a quality loam-based compost blended with 20–30% perlite or coarse sand for improved drainage. 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

Citronella Grass sits happiest at around 50–80% humidity and 15 to 40°C (59 to 104°F). Thrives in the warm, humid conditions of its tropical homeland. In dry, low-humidity environments (especially when grown indoors or in centrally heated rooms in winter), leaf tips may turn brown. Increase humidity by grouping plants, placing on a pebble tray with water, or using a humidifier during winter indoor storage. If you keep the room above 15 to 40°C 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 citronella grass sparingly. Feed with a balanced, nitrogen-rich fertiliser (e.g. general-purpose 10-10-10 or a grass fertiliser) monthly from spring through late summer to support rapid foliage growth. In containers, where nutrients deplete faster, a monthly liquid feed at half to full strength during the growing season is recommended. Withhold feeding entirely during winter when growth is minimal. 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 citronella grass in the Growli community. Each is annotated with the most common cause so you know where to start.

• Cold damage / frost kill — Cymbopogon nardus is a true tropical and will be killed to the ground — or to the roots — by frost. In USDA Zones 9 and below, bring container plants indoors before the first frost (typically when nights drop below 10°C). Overwinter in a bright, frost-free greenhouse or sunny room, keeping the soil barely moist.
• Leaf tip browning — Brown, dry leaf tips are most common during winter indoor storage, caused by low humidity and dry central heating. Trim off brown tips with sharp scissors to maintain appearance. Increase humidity around the plant and keep away from radiators or heating vents. Occasional deep watering helps if roots have dried out.
• Pot-bound crowding / loss of vigour — Citronella grass is a vigorous grower that rapidly fills and splits containers. Root-bound plants produce less foliage and dry out extremely quickly. Repot into a container one or two sizes larger each spring, or divide the clump — separate the dense rhizomatous base with a sharp spade or saw and replant sections in fresh compost.

Propagation

Divide established clumps in spring once night temperatures are reliably above 15°C. Dig up the clump, separate sections with a sharp spade or knife — each division should have several healthy culms and a portion of the root mass — and replant immediately. Container divisions can be repotted into fresh compost. In frost-prone climates, start divisions indoors under bright light before the last frost date and move outside once temperatures warm. 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

Citronella Grass is mildly toxic to pets. The ASPCA lists Cymbopogon nardus (citronella grass) as toxic to dogs and cats, noting it can cause symptoms including skin irritation, gastrointestinal upset (vomiting, diarrhoea), muscle weakness, and depression if ingested in significant quantities. The essential oils are the primary irritant. Keep pets away from the plant and especially away from concentrated citronella oil products. 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.

Citronella Grass deep-dive guides

Every aspect of citronella grass care, each with its own calibrated guide:

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

Featured in these plant shortlists

Citronella Grass 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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Citronella Grass is also known as Citronella Grass, Nardus Grass, and Sri Lanka Lemongrass.

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