conifer trees

Three questions for you - 1. Are they in pots or in the ground? 2. Have you been cutting them back? 3. Are they Leylandii?
If they are in pots, amazing though it may seem, they may need watering! If you have been trimming them, you may have cut into the old wood and then, sadly, they don't regenerate. If they are Leylandii, are you aware that there's a virus doing the rounds that kills them? - So now it's over to you to think about the three questions! If none of the above apply to you, then tell us and I'm sure someone will have another answer.