Vegetation data from botanical field survey of trials of selective herbicide impacts on tor-grass (Brachypodium pinnatum s.l.) control at Martin Down NNR, England. The data relate to 50 cm × 50 cm quadrats placed in herbicide treated and control plots in a replicated experiment, including a baseline (pre-treatment) survey in 2012 and three surveys after repeat treatments in 2013, 2014 and 2015. Data include percentage cover of plant species, bare ground and plant groups (total grasses, total forbs) as well as data on plant indictor status and Ellenberg N value. The data cover areas of both sparse B .pinnatum cover, with the goal of preventing B. pinnatum from increasing to dominance, and dense B .pinnatum cover, with the goal of reducing B. pinnatum cover to a level which allowed the reestablishment of other calcareous grassland species. Data have been used to analyse herbicide impacts on the cover of target species B. pinnatum and non-target species groups (other grasses, forbs, positive indicators, negative indicators, arable indicators), as well as community level analyses (Ellenberg-N weighted cover, DCA). Full details about this dataset can be found at https://doi.org/10.5285/43095c2d-b959-4216-8362-0fb18deed1e6