In this section, I will elaborate on how I plan instruction differently for grades five through eight. In all my classes, we will learn a different poem each marking period that relates to the theme of our unit and/or to language structures we are studying.
I use poetry in my classes starting in fifth grade, where students have an average age of ten years. In general I have found that in the fifth and sixth grades students benefit most from poems or songs with simple concepts based around vocabulary themes. Simple, related vocabulary helps students learn words and phrases in relation to each other, which allows them to implicitly categorize and classify the words in their heads.
In planning for sixth grade poetry work, I try to revisit vocabulary learned in fifth grade in new ways. That helps give the returning sixth graders a foundation off of which to build, while at the same time giving the new sixth graders an opportunity to build much of the same vocabulary as the returning students.
In seventh grade students can start to handle some more complex language or conceptual learning. Basically, some will "get" the conceptual learning and some will function at a surface understanding. While that is also true for eighth graders, they can begin to handle more and should indeed be introduced to slightly more complex themes. This same continuum comes into play within each class, as slower-progressing students can function at a surface understanding, focusing on pronunciation and memorization of terms, while others are able to adopt phrases and apply them in different ways.
As you can see, much of the differentiation work starts with the choice of poem. It is important to consider the composition of each class of students before deciding to use a particular poem. It must fit the needs of the diverse student population within each class.