We contribute Mindful Garden, an Augmented Reality Lens for Co-Located Mindfulness. HCI research has increasingly supported designing technology to support mindfulness. Augmented reality and sensors which detect biosignals both have the potential to support creating mindful experiences, by transforming people's environments into more relaxing spaces and offering some feedback to help people make sense of their physio-psychological states. We will demo Mindful Garden, a system for supporting reflection on biosignals in a mindfulness experience where two people are physically co-located. Mindful Garden has one person guide the other through meditation, representing the guided individual's biosignals as flowers in a shared augmented reality environment. We leverage Snap Spectacles and a Muse 2 headband, showing the promise of ready-to-use consumer technologies for the purpose of mindfulness and well-being. To overcome technical limitations in accessing, our demo illustrates a novel pipeline for real-time biomarker data streaming from the Muse 2 to the AR lens in the Snap Spectacles.