Radio observations provide a unique view of AGN. New low frequency observations with LOFAR are allowing us to build statistically large samples at high redshifts to study the evolution of the different accretion modes of radio-loud AGN. Here we present a new deep ($120$\,$\mu$Jy\,beam$^{-1}$), high resolution ($5 \times 7$ arcsec) image of the Bo\"otes field at $150$\,MHz with LOFAR. The LOFAR radio catalogue is combined with the optical-infrared data available in this $7$ square degree field. We use SED fitting to determine the host galaxy properties, including stellar mass and rest frame colours. Additionally, we use SED fitting, including the FIR emission, to separate High Excitation and Low Excitation radio-loud AGN (HERGs and LERGs), and use this information to study the the properties of their host galaxies out to redshifts of about 2.