Common Name | Citronella Plant, Mosquito Plant |
Botanical Name | Cymbopogon nardus |
Family | Geraniaceae |
Plant Type | Herbaceous perennial |
Mature Size | 1 to 2 feet tall and wide |
Sun Exposure | Full to part sun |
Soil Type | Well-drained sandy loam |
Soil pH | 5.8 to 6.3 |
Bloom Time | Summer |
Flower Color | Pink, purple |
Hardiness Zones | 10-11 |
Native Area | South Africa |
Citronella Care
Citronella plant is a low-maintenance plant with a shrubby growth habit if grown in the right conditions:
- Provide citronella with six hours of cool direct morning sunlight per day, but prefer shade in the afternoon.
- Plant them in the spring after the last frost.
- Space plants 12 to 18 inches apart, placing them a foot or so deep.
- Keep soil slightly moist and prevent standing water, only adding more when the top inch feels dry.
- Add compost mixed with peat moss and perlite to the loamy, sandy, well-drained soil.
- Fertilizer is not needed but is helpful for young or potted plants.
Planting
Choose a pot at least 12 inches deep and twice as wide as the root ball. Use nutrient-rich soil that drains well (like potting soil mixed equally with sphagnum moss and sand). In cooler growing zones, plant citronella in the garden when overnight temperatures hit 50 degrees Fahrenheit or above.
Set plants 18 to 24 inches apart in fertile, well-draining loam, ensuring the root ball is buried around one foot deep. Amend soil with compost or other organic material, when needed. Seeds can be sown directly in the ground by sprinkling them lightly over the soil one to two weeks after the final frost when the soil has warmed in the spring.
Light
Give citronella plants six hours of full sunlight, daily, but they benefit from afternoon shade, especially in southern growing zones.
Soil
Plant citronella in slightly acidic, sandy, or chalky loam with a pH level of 5.8 to 6.3. This soil is where it will grow best, but the plant will adapt to any soil type as long as it drains well. The health of your garden soil can be improved with a mixture of compost, peat moss, and perlite to better support citronella plant growth.
Water
Water potted plants regularly throughout the growing season. Check the top inch of soil every few days and irrigate when it’s dry. For in-ground plants, water regularly until established then once every other week. When mature, garden-grown citronella plant do not require much water. However, if leaf tips and edges start to turn brown and crispy, increase watering to once a week.
Temperature and Humidity
Choose an area that gets cool sun and afternoon shade for your citronella plant—especially in southern zones where the heat is high for extended periods of time. They are hardy and tolerate a range of temperatures, but damage can occur in freezing or excessively high temperatures. Humidity levels of 40 percent or higher benefit this native to the tropics.
Fertilizer
Apply a liquid NPK 20-20-20 fertilizer to young and potted plants. Dilute fertilizer by half strength and feed plants once every two to three weeks. Otherwise, mature citronella does not need much fertilizing.
Pruning
Encourage bushy growth and a full shrubby appearance by pinching out the growing tips of citronella plants throughout the growing season.
Propagating Citronella
The most common way to propagate a citronella plant is by cuttings. To grow a citronella plant from a cutting, gather garden snips, a small 4-inch pot, and a well-draining potting mix. Rooting hormone and a plastic covering for the pot are optional.
- Take a cutting with at least four leaves from the citronella plant’s new growth, removing all but the top two leaves and keeping the two leaf nodes at the base of the stem.
- Fill a 4-inch pot with a well-draining fertile potting mix.
- Dip the base of the cutting in rooting hormone, covering the two nodes at the bottom.
- Use your index finger or a pencil to make a hole in the center of the pot, then insert the cutting into the hole, leaving the top leaves above soil level.
- Lightly tamp soil around the stem to keep the cutting upright.
- Place a plastic dome over the cutting to improve humidity. Or mist the leaves every few days.
- Place the cutting in a sunny location and keep the soil moist. Roots should establish in about one month. Check by gently pulling on the stem. Resistance indicates roots have formed and the plant can be moved to a larger pot or set out in the garden.
How to Grow Citronella From Seed
Citronella is more often purchased as a potted nursery plant but is grown easily from seed.
Start Seeds Outdoors
Wait until the ground has warmed. This will happen about two weeks after the final frost, depending on the growing zone. Choose an outdoor location with at least six hours of sun daily, then scatter seeds over the soil and cover lightly. Keep soil moist to aid germination. Thin garden plants to 18 inches apart when seedlings reach about 1 inch tall.
Start Seed Indoors
Fill small 4-inch pots or a seed starting tray with a lightly moistened potting mix. Equal parts potting soil, sphagnum moss, and sand are a good combination. Scatter several seeds on top of the medium and cover lightly. Place a plastic dome or covering over the pot or tray to aid germination. Then, set them in a warm, sunny spot and keep them moist. When seedlings emerge, remove plastic and thin plants to one or two per pot, separating them into larger pots as needed as they grow.
Potting and Repotting Citronella
As annuals in cooler growing zones, citronella plants shouldn’t need to be repotted more than once, even if you plan to overwinter indoors. Keep in mind the mature size of the plant at around 2 feet tall and wide so choose a pot large enough to accommodate the growth.
Citronella is fairly drought tolerant so you can use a clay and ceramic pot provided it has good drainage. The container needs to be 12 inches deep and twice the width of the rootball. Use a light potting mix that drains easily.
Overwintering
Container-grown citronella plants can be moved inside to a warm, sunny window when nighttime temperatures remain below 45 degrees Fahrenheit. Remove dead or damaged leaves and prune stems back by as much as one-third, making your cuts just above a leaf node. Irrigate deeply but less frequently, allowing the soil to dry out slightly between waterings. Feed citronella once or twice during winter with a liquid houseplant fertilizer diluted to half strength.
Common Pests and Plant Diseases
Scented geraniums are relatively disease free but they do attract sap-sucking pests like whitefly, aphids, weevils, leafhoppers, and mealybugs. They are also susceptible to root rot and crown rot. A strong spray of water can eliminate pest problems when discovered early.
If your plant becomes infested, you may need to repot it with fresh planting material and treat it with repeat applications of insecticidal soap until the pests are gone. Ensure you are not keeping your plant in standing water and that the soil can appropriately drain to prevent rot.
How to Get Citronella to Bloom
In its hardiness zones of 10 to 11, the citronella plant remains evergreen and can bloom year-round.
What Do Citronella Plant Flowers Look and Smell Like?
Small flowers open in clusters with five lavender-pink petals, similar to the flowers of zonal geraniums. A broad dark purple mark brushes the uppermost petals for a subtle but striking two-toned look. The fragrance comes only from the foliage so the flowers are unscented.
How to Encourage More Blooms
Deadhead spent flowers and pinch back growing tips throughout the season to add fullness to your plant. A balanced liquid fertilizer reduced to half strength can be applied every three weeks.
Common Problems With Citronella
Citronella-scented geraniums are sturdy plants that aren’t troubled by many problems. However, this plant does require some maintenance to keep it tidy.
Thin, Leggy Appearance
Plants that receive fewer than six hours of sunlight may extend toward available light giving them a straggly, leggy appearance. Plant or place pots where they receive adequate light. Regularly pinch back growing tips throughout the season to encourage bushier growth.
Brown Leaf Tips and Edges
Citronella plants are fairly drought-tolerant but do need regular watering, especially during hot, dry periods. Brown leaf tips and edges are signs the plant is dry. Water deeply and consider watering more frequently.
Damping Off
Damping off is a fungus that will manifest in brown, limp seedlings. It thrives in cold, damp soil and can kill your seedlings. Make sure you do not overwater your plants and that you space them at least one foot apart to keep air circulating.
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When its leaves are crushed and the essential oils are released, they can be a deterrent to mosquitos.
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Citronella and lemongrass are not the same plant. Citronella has a much more potent fragrance and is not edible in the same way lemongrass is.
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Citronella, lavender, marigolds, and rosemary are some of the best plants to repel mosquitoes.
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Citronella plants can be toxic to humans, causing skin irritation, and also to cats and dogs. It can also be prone to root rot if you overwater the plant.
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