Swendara is a root herb that is used in Sri Lankan cooking. The botanical name for Swendara is “andropogon muricatus” (possibly the same thing as “vetiveria zizanioides”). The sanskrit name is “usira”, the Bengali name is “cus-cus” plant or “khas-khas” plant and the Indonesian “akar wangi”.
Swendara is an herb used in Sri Lanka cooking. A substitute is Lemongrass or Galangal.
Vetiver (Khus) is also used as a flavoring agent, usually through khus syrup. Khus syrup is made by adding khus essence to sugar, water and citric acid syrup. Khus Essence is a dark green thick syrup made from the roots of khus grass(vetiver grass). It has a woodsy taste and a scent prominent to khus.
The syrup is used to flavor milkshakes and yogurt drinks like lassi, but can also be used in ice creams, mixed beverages like Shirley Temples and as a dessert topping. Khus syrup does not need to be refrigerated, although khus flavored products may need to be. 
Medicinal uses of Andropogon muricatus (Khus-Khus-Vetiver)
The root decoction of Vetiveria zizanioides is taken internally for nervous and circulatory problems, and externally as an all around tonic bath, to ease muscle pains, and for treating lice.
It strengthens central nervous system, helpful in treating insomnia, anxiety and stress related disorders. The main constituents are A- and B- betivone, zizanal and epizizizanal found in vetiver root oil.
Zizanal and Epizizanal exhibits insect repellent activity which in turn gives good results in fumigation. Vetiver root oil is also used in preparation of perfumes due to its good aromas.