Citronella Plant: How to Grow and Care For Mosquito Plants

A healthy citronella plant needs 6+ hours of sun, fertile well-drained soil, and water only when the top inch dries out — but it will not repel mosquitoes as a living plant.

That last part surprises nearly everyone who buys one. The citrus-scented geranium sold as “mosquito plant” (*Pelargonium citronellum*) produces an oil that works in candles and sprays, but the living foliage sitting on your patio releases next to nothing into the air. Studies from the University of California confirm crushed leaves work briefly at close range, while an intact plant offers no measurable mosquito protection. Grow it for its lemony fragrance, its lavender-pink blooms, and how good it looks spilling over a pot — just don’t expect it to clear the yard.

What Is a Citronella Plant — And What It Is Not

The plant sold as citronella at garden centers is a scented geranium (Pelargonium citronellum), not true citronella grass (Cymbopogon nardus). True citronella grass is a tall, clumping perennial in the lemongrass family, and its oil is what goes into commercial repellents. The geranium version is compact, grows 2–3 feet tall, and produces clusters of small pink or lavender flowers throughout the growing season. It’s a tender perennial — evergreen only in USDA zones 9 through 11, treated as an annual or overwintered indoors everywhere else.

Sun and Soil Requirements

Citronella needs at least 6 hours of direct sun daily, ideally morning sun with afternoon shade in hot climates like the inland South or desert West. Full all-day sun in extreme heat scorches the leaves and dries the plant out faster than it can recover.

The soil must drain sharply. Moderately rich, loamy or sandy loam soil with a pH between 6.0 and 7.0 is ideal. For pots, mix standard all-purpose potting soil with 20–30% perlite or pumice to keep the root zone from staying wet. Citronella can’t handle soggy feet — root rot is the most common killer of this plant, and it happens fast in soil that holds moisture too long.

Space plants 18–24 inches apart in the ground. For containers, pick a pot at least 12 inches deep and wide enough to fit twice the diameter of the root ball. Unglazed clay pots help by wicking excess moisture away from the roots.

When and How to Plant

Set plants out in spring after the last frost passes and the soil warms. In most climates that means mid-to-late May, when nighttime temperatures stay reliably above 50°F. Bury the plant at the same depth it was in its nursery pot, water it in well, and let the top inch of soil dry out before the next watering.

Citronella Plant Care Summary

The Watering Sweet Spot

Overwatering is the single fastest way to kill a citronella plant. During spring and summer, water when the top inch of soil feels dry to the touch — then water deeply until it runs from the drainage holes. In hot dry spells that may mean every other day for potted plants and twice a week for in-ground plants. During fall and winter, let the top two inches dry out completely between waterings.

The pot checks everything: a small pot in full sun can need water daily; an oversized pot holds moisture too long and invites root rot. Always use a pot with drainage holes — citronella won’t survive standing water for more than a day or two.

Fertilizing for Fragrance, Not Foliage

Light feeding produces the strongest lemon scent. Use a balanced liquid fertilizer at half strength every 4–6 weeks during the growing season, or a slow-release granular fertilizer applied monthly. Overfeeding pushes lush, soft growth that smells less and is more vulnerable to pests like whiteflies and spider mites.

Pruning for Shape and Fullness

Citronella naturally grows leggy if left alone. Pinch the soft tips of new growth every few weeks during spring and early summer to encourage branching. In mid-summer, shear the plant back by 20–30% to reset its form and promote a second flush of blooms. Trim any leggy stems back to a leaf node where you want new growth to emerge. The cuttings root easily if you want more plants.

How to Propagate Citronella (Two Methods That Work)

Stem cuttings are the fastest route. Cut a 3–6 inch stem just below a leaf node, strip off all but the top two leaves, dip the cut end in rooting hormone (optional — it improves success but isn’t required), and place it in moist potting mix. Cover the pot with a clear plastic bag to create a mini greenhouse, and set it in bright indirect light. Roots form in about a month. Harden off the new plant by gradually removing the bag over a week before transplanting.

Layering is nearly foolproof. Bend a low stem down to a separate pot of soil, bury a section sideways at a leaf node, and leave the tip exposed. Place a small rock over the buried section to hold it in contact with the soil. Roots appear in a few weeks. Once the new plant is established, cut it from the mother.

Will This Plant Survive Winter?

Citronella will not survive a freeze. In zones 9–11 it stays evergreen outdoors year-round. In every other zone you have three options: treat it as an annual and replant next spring; dig it up and bring it indoors before the first frost; or take cuttings in late summer and overwinter those indoors as small plants.

Indoor citronella needs a bright south- or west-facing window, or a grow light running 12–14 hours a day. Rotate the pot weekly so it doesn’t lean toward the light. Water sparingly — let the top two inches dry out — and don’t fertilize more than once or twice all winter.

Common Mistakes That Kill Citronella

Three errors account for nearly every dead citronella plant:

• Overwatering. The soil must dry between waterings. Standing moisture invites root rot, and once that starts the plant cannot recover.
• Oversized containers. A pot too large for the root system holds water the roots can’t reach, creating a stagnant wet layer at the bottom. Use a pot that fits the root ball with 1–2 inches of clearance.
• Wrong light balance. Too little sun produces weak, stretched growth. Too much afternoon sun in a hot climate scorches leaves into crispy brown edges. Morning sun + afternoon shade is the formula.

Can Citronella Be Grown From Seed?

Citronella geraniums are almost always grown from cuttings, not seed. True citronella grass (Cymbopogon nardus) can be grown from seed and is a completely different plant — it grows 4–6 feet tall, spreads aggressively, and contains much higher oil concentrations. Most garden centers selling “citronella plants” are selling the geranium, which does not produce viable seed reliably.

If you want the grass instead, look for Cymbopogon nardus or Cymbopogon winterianus seed or starts. That plant actually contains the repelling oil, though it still needs to be extracted or burned to be effective — the living grass won’t clear mosquitoes either.

The Truth About Mosquito Repellent

The most persistent myth in gardening: a potted citronella plant keeps mosquitoes away. It doesn’t. A 2023 University of California study confirmed that the essential oil concentration in the living plant’s leaves is far too low to affect mosquito behavior at any distance. Crushing a leaf and rubbing it on skin provides brief, local protection (measured in minutes). An intact plant on your patio table provides zero measurable repellency.

If mosquito control is your goal, skip the potted plant and use a DEET-based repellent or a citronella candle — the candle’s heat vaporizes the oil into the air, which the living plant cannot do.

Your 30-Second Citronella Quick Start