Planetary nebulae (PNe, PN for singular) are very important as a means of chemical enrichment of the Milky Way, recycling elements such as carbon and nitrogen back into the ISM. Knowledge of their number is crucial for modelling the chemodynamical evolution of the Galaxy. The recent imaging survey of the galactic plane for extended H2 emission-line sources (UWISH2) has revealed 168 candidate planetary nebulae, with no previous entry in SIMBAD. More than 90% of these do not appear in Hα surveys such as IPHAS or SHS. It is thought that a large population of PNe are invisible at optical wavelengths, obscured by dust. It is therefore necessary to move to infrared observations in order to reveal this obscured PN population. K-band (2.0-2.4 μm) spectroscopy has been carried out on 30 candidate PNe, to reveal their evolutionary status. A multitude of ro-vibrational transitions of H2, along with recombination lines of H (Brγ) and He are seen. We find that 26 of these are likely to be true PNe, while the other 4 are likely proto-planetary nebulae (PPNe) - these have central stars which are not yet hot enough to ionize their surrounding environments. One object shows red and blueshifted components, implying fast, collimated outflows. Future observations, including narrow-band imaging of Brγ and HeI, along with integral field spectroscopy of some of the more interesting objects, will allow us to investigate the shaping mechanisms occurring in PNe – an actively open area of research.