These data are the annual records of observations of phenological phases of plants in the International Phenology Garden (IPG) at Alice Holt, Hampshire. The IPG network consists of replicated gardens across Europe, where the timing of events such as leaf unfolding, flowering, fruiting, autumn leaf colour change and leaf fall are recorded. The scientific aims of the IPG programme are to monitor environmental changes, conduct climate impact studies, develop phenological models, calibrate remotely-sensed data, and the calculation of phenological maps. These data are given as the day of year for each phenological phase, coded as: MS (May shoot); UL (leaf unfolding); JS (St John’s sprout, or Lammas growth); BF (beginning of flowering); FF (general flowering); RF (first ripe fruits); CL (autumn colouring); FL (leaf fall). For further details, see http://ipg.hu-berlin.de. Attribution statement: Users of the data must acknowledge Forest Research and the International Phenology Garden network.