I have 4 rose bushes that are producing pink roses. They don't seem to be very old. I've noticed around the bottom of some branches they are turning brown where they should be green. does this mean they are dieing? I live in a rent house so they were already here. I just want to know the basics on how to help them bloom and stay healthy. I don't know much about gardening, but would like to learn about browning leaves, stems, petals, etc. and what part to cut. I live in Texas I'm not sure if the climate will help answer this question.