Not a good idea, even without knowing what the 6 ft evergreen is. If the roots damage the drain, you'll be responsible for the (very expensive) repair.

Thankyou. Any suggestions for plant with shallow roots that I could plant near drain for screen.

There are none, I'm afraid. Any plant which is big enough to make a screen will have deep roots.

What are you trying to screen off? A fence would seem to be the answer.