It really depends if they are truly dead or not. Scratch the skin of a branch to see if you see any green at all. If the branches are brown and break easily, then your plant is dead. It does sound like they didn't get enough water. Perhaps your terra cotta pots are new and sucked the moisture out of the soil. New terra cotta pots can absorb a lot of soil moisture until they are ""seasoned"". I often soak new terra cotta pots in water for 24 hours before I use them."