We have about 18 hybrid tea roses of different varieties and this spring all of them are growing very poorly and have many curled leaves. They were planted about 10 years ago and this is the first time this has happened. They were fertilized with a granular rose fertilizer (3 in 1) about a month ago. There are no signs of bugs/pests. What do you think is the problem and what can we do to improve the situation?

Thank you.