Be protected by a plant, a tufty one (6)
I believe the answer is:
iberis
'one' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how one could define the other.
'be protected by a plant a tufty' is the wordplay.
I cannot quite understand how this works, but
'be' is within the answer.
'plant' could be 'iris' (type of flower) and 'iris' is found in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
(Another definition for iberis that I've seen is " flower ...".)