For many children across the globe, whether in low or high income nations, growing up in the 21st century will mean living in overcrowded, unsafe and polluted environments which provide limited opportunity for natural play and environmental learning. Yet Agenda 21, the Habitat Agenda and the United Nations Convention on the Rights of the Child all clearly articulate the importance of urban environments as the context for supporting children's sense of place, community identity and empathy with the natural world. I will argue in this paper that these attributes are all key drivers for supporting children in their role as future decision makers and environmental stewards. Extending Winnicotts' concept of "holding environments" beyond the social and cultural aspects of communities as sites for placemaking I draw a link to the value of botanical gardens and other green spaces in cities as the "holding environments" for children's environmental learning. I will construct an argument around the premise that to participate in, and contribute to, global sustainability--our children need places and the opportunity to engage, connect and respond to nature. (Contains 5 figures.)