This is why I teach poetry to high school students

Because I can teach all the literary devices I want them to learn throughout the year by using poems for examples:

Metaphor in "Dreams" by Langston Hughes:

"For if dreams die, life is a broken-winged bird that cannot fly."

Repetition in the same poem:

"Hold fast to dreams... Hold fast to dreams...."

Theme (with perhaps a life lesson thrown in):

What is the poet saying here? Don't let go of your dreams or you become, in a sense, crippled, unable to move forward. Is there something important that you want to do in your life? Whatever it is, you can do it. The path to your goal may not proceed in a straight line, but keep that end destination in your sights; you'll get there. How did the poet know this? He lived it.

A more challenging theme in a different poem by Langston Hughes:

"What happens to a dream deferred? Does it dry up like a raisin in the sun?"

Point of view and tone in "Bike Ride with Older Boys" by Laura Kasischke.

(I do this one early in the year with my freshmen because I want them to learn that reading a poem is sometimes like unlocking a small cupboard door to find a bit of truth just sitting on the shelf, waiting to be discovered, and to show them that in poetry, titles can be an essential key.)

The first line of the poem is this: "The one I didn't go on."

The next two lines are: "I was thirteen/and they were older."

In this poem I love "My afternoons/were made of time and vinyl" and "I have been given a little gift." We don't know what the gift is until we're nearly finished reading the poem. Some students are mystified by the lines "When I/stand up again, there are bits of glass and gravel/ground into my knees." They ask hesitantly, "What happened? Did she fall off the bike?" Others, when the impact of the narrative hits them, say, "ohhhh" in soft tones, and I know they are moved by it, perhaps even warned by it.

(As an aside here, that 'title as key' concept can also be seen in "Another Reason Why I Don't Keep a Gun in the House" by Billy Collins, which never references a gun at all in the poem, but does reference a dog that barks incessantly.)

Some poems should just be fun, so we do "Summer" by Walter Dean Myers, but they're still learning assonance, alliteration and internal rhyme as we go:

"Bugs buzzin from cousin to cousin/juices dripping/running and ripping" and

"Lazy days, daisies lay/beaming and dreaming...."

And there must be classics because, well, if you don't know Frost, you're not American.

"Whose woods these are, I think I know."

"Two roads diverged in a yellow wood."

"Something there is that doesn't love a wall."

Billy Collins is my hero, of course, and sometimes it's fun, especially with high school students, to discuss extended metaphor by reading "Schoolsville."

("Their grades are sewn into their clothes/like references to Hawthorne./The A's stroll along with other A's./The D's honk whenever they pass another D.")

And speaking of classics, we read "To the Virgins, to Make Much of Time" so that we can discuss the concept of carpe diem, but I introduce it to them by showing them the scene from the movie Dead Poets Society in which Robin Williams as Mr. Keating has one of his new students read the poem.

I follow that by teaching them "O Captain! My Captain!" (because, in my humble opinion, Whitman was the most courageous American poet of his time), and then we watch the heartbreaking scene in Dead Poets in which Keating's students stand upon their desks in deference and respect, each one proclaiming "O captain my captain!"

I have shared tears with some students after such a lesson.

I allow Emily Dickinson to teach them that "hope is the thing with feathers" and also that "I'm nobody" can be a strong statement of defiance for an introvert. 

I teach them "Richard Cory" by Edwin Arlington Robinson toward the end of the school year because I want them to understand how subtle poets can be:

"He was a gentleman from sole to crown/clean favored and imperially slim," but mostly because I want them to fully understand what isolation can do to people, how desperate and alone it can render someone who feels incapable of making a human connection with anyone else. I tell them to consider the folks around them... and who might be suffering despite walking among them as if everything is fine. At fourteen and fifteen, they are still challenged to find empathy and compassion. ("If he killed himself, he's stupid. That's just stupid.") But we work on it. We work on it.

Generally we end the year with Frost's declaration that "Nothing gold can stay" because I want to remind them about that whole "seize the day" attitude and that, while they are perfect—just as they are—life is going to lob some considerably large stones at them, which may alter them. But that's ok. Because "hope springs eternal."