Environmentally induced epigenetic change enables plants to remember past environmental interactions. If this memory capability is exploited to prepare plants for future challenges, it can provide a basis for highly sophisticated behaviour, considered intelligent by some. Against the backdrop of an overview of plant intelligence, we hypothesise: 1) that the capability of plants to engage in such intelligent behaviour increases with increasing modularity, and; 2) that more faithful inheritance of epigenetic information in clonal plants, in conjunction with information exchange and coordination between connected ramets, is likely to enable especially advanced intelligent behaviour in this group. We therefore further hypothesise that this behaviour provides ecological and evolutionary advantages to clonal plants, possibly explaining, at least in part, their widespread success. Finally, we suggest experiments that could allow for assessing intelligent behaviour and the role of epigenetic memory in clonal species.