There is a place where the sidewalk endsand before the street begins (1-2)
As we read the poem, the "place where the sidewalk ends" becomes a refrain, reinforcing over and over again the idea of a land beyond the city, where our imagination is freer to wander and wonder.
And there the grass grows soft and white,And there the sun burns crimson bright (3-4)
The details in these lines show us, for certain, that we're not dealing with the literal end of the sidewalk here. If we were, the grass would be green and the sun would be yellow. Instead, we've delved into the world where everything is possible, if only we can dream it.
And there the moon-bird rests from his flightTo cool in the peppermint wind (5-6)
Even though the world we've found ourselves in isn't actually a real place, we're able to picture it quite well, because of all the details our speaker gives us. The world, while imaginary, is being created for us in a very real way. Maybe real and imaginary aren't as opposite as we might think.