香根草（又名培地茅、岩兰草，国际通用名称为Vetiver，学名Chrysopogon zizanioides）,是禾本科多年生草本植物，原产于印度次大陆与中南半岛，经人工栽种，目前广泛分布于亚洲、非洲、美洲与澳洲热带与亚热带地区。

香根草耐暑、耐涝，可度过寒冬，分蘖丛生，生长快速，茎梗直立有节，抽穗成熟一般高达1.5米（4.9英尺），叶子对生、长窄且硬，圆锥花穗顶生、花紫色，不易结籽，须根系繁盛呈网状向下生长，生长于矮树林区，却相对显得十分高大，一般深达2米（6.6英尺）至3米（9.8英尺），有香气。香根草目前主要被种植作为侵蚀控制，也会将其根部提炼成香根草油（Vetiver Oil），作为精油或香水的原料，而南亚传统上会作为草药使用。

Chrysopogon zizanioides, commonly known as vetiver (derived from the Tamil: வெட்டிவேர் veṭṭivēr) is a perennial bunchgrass of the Poaceae family, native to India. In western and northern India, it is popularly known as khus.

Vetiver is most closely related to Sorghum but shares many morphological characteristics with other fragrant grasses, such as lemongrass (Cymbopogon citratus), citronella (Cymbopogon nardus, C. winterianus), and palmarosa (Cymbopogon martinii).