Abstract Distribution patterns (frequency and percentage cover) of 18 forest plant species were studied in 34 ha of mixed deciduous forest (Muizen Forest, north Belgium). Stands varied in age between 6 and more than 223 years and both slow and fast colonizing species were studied. Detailed land use history data were combined with the species distribution maps to identify species‐specific colonization sources and calculate colonization distances. A multiple logistic regression model was constructed with four covariables: pH (which can impose limits on the potential species‐distribution), secondary forest age, distance from nearest colonization source and age–distance interaction, to allow us to account for the gradual completion of colonization over time. We could distinguish species which are limited by both dispersal and recruitment ( Primula elatior , Arum maculatum and Lamium galeobdolon ), mainly by dispersal ( Anemone nemorosa, Deschampsia cespitosa ), mainly by recruitment ( Paris quadrifolia and Polygonatum multiflorum ) and by neither ( Geum urbanum , Ranunculus ficaria , Glechoma hederacea , Aegopodium podagraria , Ajuga reptans , Adoxa moschatellina and Oxalis acetosella ). The low colonizing capacity of ancient forest plants cannot be attributed to a single cause; rather both dispersal and recruitment are limiting but the relative importance varies.