Ask Mr. Smarty Plants

We are assuming you mean Miscanthus sinensis grass var. "Morning Light," and also assuming you meant you had planted it 3 days ago, and now the ends of the grass are shriveling.

In the first place, any time you see a plant scientific name ending with "sinensis," you can bet it is not native to North America. Usually, it means that plant is native to China; in this case, it also includes Japan, Korea and other Far Eastern countries. The Lady Bird Johnson Wildflower Center is committed to the use, protection and propagation of plants native not only to North America but to the area in which the plants are being grown. This article from Floridata on Miscanthus sinensis will possibly answer some of your questions. Your grass may just be suffering from transplant shock, and needs a little trimming off the top. Check the referenced article to see if you have the grass in the right amount of sun, and if it is getting enough water. Beyond that, please notice the Warning at the bottom of that article:

"Chinese silver grass is invading and disrupting native plant communities in many places from the southeastern United States to California and the West Coast." 

That is one of the reasons we recommend using only plants native to an area; the non-native, with no natural competition or predator, can become invasive, forcing out natives and destroying natural habitats.