Boy chalks beanstalk or garden all over the pavement/sidewalk of his town, possibly as part of an art competition. Then rain washes it away, leaving only what was done in an alley way.
Children’s fiction - read in 1980/1990s. He was given an allotted space to do his chalk art but he went up the walls and through alley ways etc. At the end it was all rained away.
Beautiful illustrations as I recall - not a chapter book but a child’s story book.
The Chalk Box Kid?
https://www.goodreads.com/book/show/785522.The_Chalk_Box_Kid
No this story plot isn’t right. In this book I think there is a town wide pavement art competition and they all get a section each and then he draws down an alley and then at the end the rain washes it away. I’m sure it’s a bean stalk vine type garden he draws.