Waugh's designs also incorporated the concept of ecology through the use of plantings characterized by natural association of plant species, in conjunction with environmental conditions. Having studied in Germany, Waugh was influenced by such Germans as Willy Lange, whom Waugh credited with the best explanation of ecological principles. Additionally, the curator and the planting foreman of the Berlin-Dahlem Botanical Garden, Dr. Adolf Engler and Dr. K. Peters, used mass plantings in response to soil and drainage. Waugh's designs were driven by these developments in vegetation use, which he believed were essential to the character of his natural style. It is no wonder that he developed a taste for native vegetation and natural scenery, considering that these elements coincided with the concept of a place's ecological scheme and overall spirit. Another conceptual requirement for Waugh's naturalistic style of gardening was the open lawn. He believed that they were the natural foundation for a natural landscape. With English influences such as the large estate garden at Stowe in England, the wide-open lawn reigned supreme, implying the values of naturalistic landscaping through little manipulation of planting arrangements and circulation patterns. The influence of the emphasis on the lawn can be seen throughout America, and although it may have lost most of the naturalistic symbolism behind it, the "great American lawn" continues to be popular today.