The poem "Roses are red, violets are blue, flowers are pretty, and so are you" doesn't have a specific author or date of origin. It's a traditional rhyme that has been around for centuries and has evolved over time.
It's similar to other popular children's rhymes like "Twinkle Twinkle Little Star" or "Mary Had a Little Lamb" - they've been passed down through generations and have no single definitive source.