These data describe the rates of filled, viable and germinating seeds from over 60 maternal juniper trees from across the UK. 12 populations from the Scottish Highlands to Southern English Downs were sampled in Fall 2023. Four different methods of seed viability testing were applied, and germination was monitored for over a year in response to nine different combinations of pretreatments and stratifications. Reproducible analyses and visualizations from an associated study are provided with an R project. This trial was conducted to determine the optimal treatment for juniper stratification and to quantify the variability in seedlot quality/viability among populations. Full details about this dataset can be found at https://doi.org/10.5285/64607f86-0228-4a03-9d87-6e36435028a1
