Could I do more for thee
The repetition
The entire stanza repeats exactly. Not a printing error—Dickinson sometimes used repetition to intensify questions she couldn't answer.
Conditional grammar
The subjunctive 'Wert thou' (if you were) sets up a hypothetical—she's comparing the addressee to something they're not.
Queen bee biology
Worker bees gather pollen for their queen. Dickinson reverses this—she's the one offering flowers, making herself the worker.