In Vlaardingen (province South Holland) an attempt is being made to manage public gardens and parks in an ecological way. The driving force behind this initiative is Ben van As who works for the local council, and has reintroduced plants as well as butterflies in one of the parks. By careful and selective planting and sowing, Van As has created several different biotopes with their natural vegetation. These include a dune slope, a small field, an orchid garden and a butterfly meadow. In the latter a wide variety of plants has resulted in an increase of the number of different butterfly species; also species otherwise not seen in the city. In 1987 an experiment was set up to reintroduce Anthocharis cardamines in the park with the food plant Alliaria petiolaris. This was not succesful due to bad weather conditions in the spring and the small size of the population which was released. The intention is to repeat the experiment this year.