Rose bush heat and insect protection
Hello: I have a rose bush in the front and back yards of my home -- I do not know the species. Once the weather gets consistently warmer, by late May or possibly a little later, rose petals have all fallen and leaves on the bushes start to yellow with many falling. Year after year this happens and year after year the bushes come back as pretty as before for a while before the cycle starts up again. I figured this was due to heat stress, but wanted to confirm and see if anything could be done to prevent leaf deterioration. Also, throughout the spring and summer both bushes are susceptible to a significant presence of very small white bugs -- i think they are aphids, but don't know for sure. I typically use Sevin dust to control, but repeated applications are necessary, where if I don't repeat after a few weeks, the bushes will be littered with leaf holes. What is the best approach to prevent insects chomping on the rose leaves? Thank you.
You probably have rose slugs, which are small and green, so they are hard to see. Here is our website info, including how to control them: http://extension.umd.edu/hgic/rose-slugs-shrubs
You should not use Sevin on roses or any other flowering plant, because Sevin is highly toxic to bees, which visit blooms.
Black spot is a fungal disease that also causes rose leaf yellowing and falling. You don't mention any spots on the leaves, but it's very common and here is the info on that, which could be helpful: http://extension.umd.edu/hgic/black-spot-roses-shrubs