I don't know if One Direction will stand the test of time. I have a niece who goes crazy for them. But the only way to judge art is to wait and see if it becomes evergreen. This takes a bit of time. Adele is a very good musician and I'd like to sing with her. But, again, time will tell if her music will become evergreen.

This quote is talking about how it can be hard to tell if something will become popular for a long period of time (“evergreen”). The speaker is referring to the boy band, One Direction, and the singer Adele as examples. They both have fans now, but it is hard to tell if their music will still be appreciated many years from now. So, the speaker is saying that only time will tell if their art will become “evergreen”.