Lemon grass is a perennial, native to India, which has become very popular as an aromatic herb in cooking, and in the production of perfume. This lemon-scented grass is also versatile in the garden and is now seen often in Arriyadh, where it has been planted as an ornamental. It grows in dense clumps up to 1.8 metres in height and about 1 metre in width. The strap-like leaves are bright bluish-green, and release a citrus aroma when crushed; they have gracefully drooping tips, making them interesting in garden borders. Typically without flowers, flowering produces inflorescences that have a nodding appearance in the wind. An attractive groundcover when planted in gravel mulch or next to a pathway, plants release their fragrance when brushed against by passers-by; they also grow well in containers. Lemon grass is not frost-tolerant, but will come back when cut to the ground. It is said to keep away mosquitoes. C. citratus needs full sun to light shade with a moist, well-drained soil. Plants are drought-tolerant, but suffer without watering. As fairly aggressive growers, they need to be divided, which is the usual method of propagation in spring; alternatively, they can be seeded. The roots are deep and strong, making plants suitable for erosion control and slope stabilisation. Cymbopogon schoenanthus, or Incense Grass, is a native Najd desert species, which also contains aromatic oil. Growing in dry, stony places, it can appear dead during the summer; after winter rain, it comes back to life and waves its flowers in the breeze.