This year after the harsh winter that we’ve had, my yuccas in the garden look very dried up and dead. Should I just leave them and see whether they will come back up and turn green or should I dig them out?
Yes, it was/is a brutal winter.
Since I do not know what kind of yucca you have, I suggest waiting a couple of more weeks to see whether it lives or goes to the compost bin. If there is a long root and it was partly protected, you may see some green.
Most yucca do best in hot, dry climates. However, some will grow in completely different environments. Many gardeners bring their smaller succulents and yuccas into their garage or shed in the winter.
If you want to read more about this interesting plant, you might try Agaves, Yuccas and Related Plants by Mary and Gary Irish, published by Timber Press.