What is the difference between citronella, lemongrass and palmarosa for a new aroma grower?

All three are hardy perennial aromatic grasses grown for essential oil by distillation, drought tolerant, multi-cut and multi-year, and suited to warm climates and marginal land, but their oils and markets differ. Lemongrass oil is rich in citral and used in flavour, fragrance, cosmetics and some pharma, and lemongrass also has a small fresh market for tea and cooking. Palmarosa oil is valued for geraniol and used mainly in perfumery, soaps and cosmetics, often fetching a higher value when geraniol is high. Citronella oil is used heavily in mosquito repellents, candles and cleaning products and tends to be more of an industrial-volume oil that competes with imports on price. In climate terms, lemongrass and citronella like warm humid conditions while palmarosa tolerates drier heat well. For a new grower, the choice should be driven by which oil you have a confirmed buyer for, not by the crop itself, because all three grow easily but only sell if you have a distillation arrangement and a buyer. Do not pick based on yield tables alone; pick based on the buyer you can actually secure. Verify oil price, the quality spec (citral, geraniol etc), and the buyer in writing before deciding.