The speaker in the poem feels a general dejection which is probably the combination of despair or depression (cause unknown) mixed with a weakened creativity or writer’s block. The speaker seeks inspiration from nature. He tries to gain strength from the storm in the first two stanzas and he tries to listen to the story of the wind. He is unsuccessful in gathering strength from this. But he does come to realize that he can’t just passively wait to be inspired by nature in the third stanza. He notes that, “from the soul itself, it should issue forth.” He then concludes that creativity, inspiration and joy come from a marriage of mental and external beauty.
The speaker cannot escape his dejection because he can’t summon inspiration from his own mind or combine it with the beauty he sees in nature. His only consolation and hope is that he wishes the Lady (Sara Hutchinson) will experience the joy he cannot. He is still dejected but this is an attempt to summon his inner inspiration outwardly. In this case, his hope is directed at another person which might be as effective as directing it toward Nature.
The title “Dejection: an Ode” might imply that the speaker is speaking to Dejection itself. This is called apostrophe: when the speaker addresses an abstract or non-human object. The speaker addresses the Lady, although she is not present, but the majority of the poem indicates a soliloquy. Since it is an “ode to Dejection,” you could make the case that he’s speaking to his own dejection (himself) or the abstract quality of dejection. But since he’s striving for inspiration, he could be addressing creativity (Imagination) and therefore, the title is purposefully misleading. Considering the idea of marriage between the mental (inner) and Nature (external), the speaker is most likely addressing his inability to connect with the world. He is separated or (d)ejected from Nature. This is more logical because the void is in him; not in Nature. Nature cannot be dejected. So, it is not Nature’s lack of inspirational fodder. It is the speaker’s mental state and his inability to connect.