did it get plenty of water even in the drought we had last year? even native & drought-tolerant plants will die if they aren't watered every day or so during the first year (if there is no rain & relentless heat). but even if you water thru a drought, a lot of plants look dead after a winter freeze but then leaves will start to pop out on lower parts of the old stems, in the spring. try snapping off the stems at the edge.. are they totally dry and dead? then go down a little further... if you encounter a lower part of the stem that is still bendable (won't snap) and is green/white inside.. then it should still be alive. most plants should be showing SOME kind of life by now anyway. if it's still alive i would prune all the dead growth off. but if the stems are hard and hollow and snap off all the way down to the bottom, the plant is probably dead & you should just start over. i'd get a new one in the ground soon before it gets too hot again.