In the 1940s, Kelly began to experiment with abstraction. But he always emphasized that his abstraction always comes from reality, from the forms that surround us: "Since birth we get accustomed to seeing and thinking at the same time. But I think that if you can turn off the mind and look at things only with your eyes, ultimately everything becomes abstract".
In 1949, while living in Paris, influenced by Matisse and Arp, Kelly began to draw simple plant forms. In his drawings of fruits, flowers and leaves, Kelly’s emphasis is on the essence of each plant, and in the clarity of the line and the shape, these drawings are a decisive connection to his abstraction. Kelly himself called his early drawings of plants the source of all his later work. In the mid-1960s he created the first group of plant lithographs.