We have 3 soft yucca plants that have been growing great for the last 6 years. They are bordering our pool. Now they seem to be totally dried out. We have cut them back hoping they would start growing, but some of the stalks are so dried out that they are just breaking off. They have been at least 5 to 7 feet tall.
How Do I Know if My Soft Yucca Plant Is Dead?
This article answers questions about dead plants: https://www.gardeningknowhow.com/plant-problems/environmental/how-to-tell-if-a-plant-is-dead-and-how-to-recover-an-almost-dead-plant.htm
Yuccas are native to the southwest, so the winter may have been too much for them. However, they're also tough hombres, and even if the stems and leaves are dead, you may see some new growth coming up from the roots.