Are strawberries perennials in zone 6, and if so, how can I ensure they thrive year after year in this climate?

Yes, strawberries are perennials in zone 6. To ensure they thrive year after year in this climate, you can plant them in well-drained soil, provide adequate sunlight, water them regularly, and protect them from frost in the winter. Additionally, you can mulch around the plants to help retain moisture and suppress weeds.