This paper presents the role of weeds and hedges as ecological refuges and sources of the most abundant and most economically important phytoseiid species Euseius finlandicus, Typhlodromus pyri and Amblyseius andersoni, on apple in Central Greece. The survey was carried out in four orchards in Zagora and Anilio (Prefecture Magnisia), in Farma (Prefecture Trikala) and in Agia (Prefecture Larisa) on a selection of plants which had been made prior to the systematic monitoring of the acarofauna. The population dynamics of E. finlandicus, T. pyri and A. andersoni were studied. E. finlandicus and T. pyri were observed on the hedge plants Rubus fruticosus, Rubus sp., Castanea sativa, Juglans regia, Cornus sanguinea, Prunus avium and Sambucus nigra while A. andersoni was found mainly on herbaceous plants. This survey explains that weeds and hedges may form natural ecological refuges and potential sources for populations of phytoseiid species when conditions are favourable for their supposed flow between those source plants and the protected crop.