The basic idea from which the Head Gardeners’ Guild association was founded came from the garden philosopher Rob Leopold (†2005) of the foundation Perennial Perspectives. The 1990s saw the start of an exchange of knowledge among the head gardeners and gardeners of the estates Twickel, Het Loo, Het Weldam and Het Warmelo, which did not go unnoticed by Leopold. He argued for a comprehensive garden culture that combines landscape architecture, horticulture and ecology. He believed that the divide between art and craftsmanship in gardening and landscape architecture should be removed and the art of gardening should be revalued. For this revaluation of the neglected horticultural perspective, the exchange of knowledge amongst colleagues is essential.