Citronella grass, or Cymbopogon nardus, is a perennial grass that originates from tropical Asia. It is also the source of citronella oi, an essential oil common in perfumes and soaps. Farmers and ranchers consider citronella to be an invasive species since it is inedible, but gardeners in California and Florida use citronella as an ornamental plant. Citronella is generally hardy in warm climates, but requires plenty of water.
Select the planting site. Citronella requires a long growing season and may not survive a cool winter. It thrives in United States Department of Agriculture hardiness zones 10 to 12. Citronella also does best in full sun.
Obtain a planting pot with a drainage hole in the bottom, and fill the pot with a general-purpose potting soil. Make a hole in the centre large enough to hold the citronella plant.
Place the citronella plant into the hole in the potting soil, so that the root ball is below the soil level. Cover the roots with soil, and pack the soil around the plant.
Water the citronella plant thoroughly, and set it outside in full sun if the overnight temperatures are above freezing. Keep the plant indoors and place it under a grow light if the overnight temperatures are below freezing.
Fertilise citronella plants weekly with a water-soluble fertiliser, according to the pot size. Water the plants daily during the growing season. They require at least 30 inches of water per year.
Divide the clumps of adult citronella grass into smaller sections with a clean, sharp knife before winter. Move some of these clumps indoors in case the outdoor plants don't survive the winter. Replant citronella grass outdoors in the spring.