Cities provide a locus for sustainability: they will soon accommodate most of the world’s population, just as increasing environmental and climate emergencies and socio-economic inequalities constitute major challenges. The concept of urban green infrastructure (UGI) offers a greenspace planning approach based on a grounded set of principles to improve the environmental health and liveability of cities. A wide variety of greenspace planning and implementation approaches is already being applied within and across countries. This paper employs UGI as a research lens to critically evaluate planning trends in Slovakia on national, regional and local levels. To this end we have analysed planning documents, interviewed greenspace agents and evaluated local good practice. Our results indicate weak instrumental support for UGI planning, as well as other systemic and procedural barriers to green infrastructure. Moreover, a comparison with observations from other European planning systems reveals notable commonalities and differences. The paper then discusses a local greening programme and bottom-up actions as potential ways to foster green infrastructure development. Local practitioners can initiate important planning processes by employing nature-based practices, engaging with stakeholders and promoting functional approaches. We propose a participatory integrated model that utilises the opportunities embedded in bottom-up actions. Our model can be adopted in higher-level planning and policymaking if appropriate operational and mediating interventions take place.