According to Nash biographer Douglas M. Parker, Nash was very close to his sister Gwen and sometimes referred to her as mother number 2. At her Wedding in Savannah "Ten year old Ogden recited a poem he had written beginning "Beautiful Spring at last is here!/ And has taken my sister I sadly fear."
Years later Nash poked fun at himself, as the wedding actually took place in January.
Parker's book, Ogden Nash - The Life and Work of America's Laureate of Light Verse, is based on many sources, including the Nash family. It's a wonderful read that details what a unique life Nash lived.