So, I've read that Epsom salts are good for roses? This spring, I planted some climbing roses. I didn't know how to shop for them, so just grabbed the healthiest looking ones. Some are doing fine. One is slow to grow, and one appears dormant. I put a little commercial composted manure in the holes before planting them. They get plenty of water and sunlight. Kind of feel like I should do something else. Any ideas?