This dataset contains root length, biomass and fungal colonisation data for Calluna vulgaris from control, drought and warming treated soils from the long term climate change experiment in Clocaenog forest. Soil samples were collected from the climate change experiment in Northeast Wales during April 2015. Roots were separated from the soil, their length and biomass measured and then analysed using microscopy for Ericoid mycorrhizae (ErM) and dark septate endophyte (DSE) colonisation of Calluna vulgaris. The experimental field site consists of three untreated control plots, three plots where the plant canopy air is artificially warmed during night time hours and three plots where rainfall is excluded from the plots at least during the plants growing season (March to September). The Climoor field experiment intends to answer questions regarding the effects of warming and drought on ecosystem processes and has been running since 1999. The root length and fungal colonisation data aims to understand how changes in soil hydrological and chemical properties have influenced Calluna vulgaris rooting behaviour and interactions with the soil microbiome. This work was supported by the Natural Environment Research Council award number NE/R016429/1 as part of the UK-SCAPE programme delivering National Capability. Full details about this dataset can be found at https://doi.org/10.5285/3d468857-f5d0-4dc4-88f3-6be6df19608b
