Evergreen in Eliot's verse 'withered with no trace of sun' (5,4)

I believe the answer is:

olive tree

'evergreen' is the definition.
(type of evergreen tree)

I don't understand how the remainder of the clue works.

(Other definitions for olive tree that I've seen before include "oil supplier" , "bearer of fruit" .)

I've seen this clue in The Guardian.

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