Once planted in soil amended with organic material your grass will thrive. Be aware of the sunlight needs of the different varieties of ornamental grass. All Miscanthus and Panicum are warm weather grasses and require full sun to perform well. Purpurascens' can tolerate a greater amount of shade. Fertilize with Miracle Grow or other general purpose fertilizers.
Grasses build a very hardy and extensive root system.
Water well the first year. Generally all grasses will do fine with minimal maintenance the second and following years.