Answer: the apples will grow after the flowers blossom.
An adverb clause is a dependent clause that serves as an adverb, in other words, it modifies a verb, adjective, or another adverb. It tells you when, where, why or how the action happens. It also contains a subject and a verb.
In this case, the clause "after the flowers blossom" is an adverb clause that modifies the verb "grow."
