How cold can plants servive

Well maybe I jumped to fast.
Planted outside first weekend of May,
Last few days it got down to 25* F
Havent had a chance to go see they are 3 hours away will this kill them they were 12"+ tall
Thoughts Please

hopefully it gets warmer quick..... won't know until you know...... but if you did know about the cold, and took appropriate measures like a thick mulching, they may be alright.