These reed like leaves are 1 to 2 feet long (about 60cms) and grow pretty much everywhere there is a hot climate. We use them for their flower scent (very rose like) and to create a natural green colouring for foods.
To prepare them, either squeeze them in water, or place water and the leaves in a blender and blend them, then sieve out the pulp. Once you've made the green scented water, you can freeze it and it will last 6 months or more without problems.