Familiar with children who "can't write poems"?
Try this no-fail method.
Tell the children you are going to make 'word bones' for a skeleton poem. Get them to brainstorm exciting pairs of words aroung a theme or picture and write them in a list with lots of space around and between. e.g rickety boat
Tell them they've made a great poem but let's see what it looks like with 'meat' on it's bones.
Children suggest extra language to 'fatten up' each line of the poem: away we sailed in a rickety boat waving back at the shore....
Use interesting pictures or discussion about children's experiences, have children jot down words. Set them to work on the skeleton and then share in groups, everyone can suggest ideas.
Make sure children have support, a buddy, thesauruses, teacher conferencing. Accept their first attempt, even in skeleton form as 'excellent'. Encourage them to try another or add meat to their first attempt.
Choose 3 or 4 children each session whose work you'll publish attractively on computer. Others can publish on computer too or on paper to make a bound book for your reading corner or a wall display. Any children not publishing can work on illustrations for the book cover or display.
Aleays have small slips of paper handy for children to attach to their work. They can then move around the tables writing positive comments on each others' slips after reading the poems.