One-half toy dinosaur, one-half rocking horse, Jeff Koons’s playful creation remains one of the artist’s most endearing figures. In 2000, Koons unveiled the first “Split-Rocker” as a monumental, flower-speckled topiary at Avignon, France’s Palais des Papes. Fourteen years later, he created the sculpture at Rockefeller Center, timed to open in tandem with his retrospective at the Whitney Museum of American Art. Inside the 37-foot-tall sculpture was an intricate system of irrigation tubes, keeping more than 50,000 flowering plants alive throughout the show’s three-month-long run. Today, Koons’s series of “Split-Rocker” vases are a similar, transient shelter—gently suspending flowers between life and death.