That is a great gift idea but a pretty wide open question since there are so many great plant possibilities and the site conditions really dictate what will and won't grow. However, that said if they have a sunny area with good drainage a rose is a good choice. There are many antique roses and modern ones too that are very tough and many are disease resistant. Some of my favorites are Belinda's Dream, Old Blush, Marie Pavie, Marie Daly, Carefree Beauty, and Livin' Easy. Do a Google search to learn more about each of these as they are quite different or submit another question to the Home Depot website asking about a particular one and I'll be happy to provide details.
Thanks for the question. Please stop in again soon!
Q&A Library Searching Tips