Certified GKH Gardening Expert
It depends on your region and how cold your winters get as to whether they can remain in the ground. In warmer regions, tulips cannot be planted in the ground year round as they need to be pre-chilled to be able to flower. However, if you live in an area with reasonably cool temps, they can be left in the ground. These articles should help should you need to lift them for storing: https://www.gardeningknowhow.com/ornamental/bulbs/bgen/preparing-bulbs-for-winter-how-to-store-bulbs-for-winter.htm, https://www.gardeningknowhow.com/ornamental/bulbs/bgen/how-to-plant-bulbs-in-the-south.htm