This is part of a poem that was stenciled on a few walls that I walked by today. The poem is actually three parts and is entitled "Flores de Basura" or "Flowers of Garbage".
Here's a rough translation, provided by Christine.
gathering the ground
and empty containers
with bags of men
sleeping in sandals
adorn the countryside
of the great city
*Cartoneros are people who collect recyclable garbage and turn it in for money. This is usually their main income.