I need to know what I did wrong-killed my double petunias
I had them planted in a bed with my yellow roses, which gets some bright sun in the late morning/early afternoon. I watered them a lot until they started looking bad. So, I figured I was over doing it and slacked off. They didn't look any better, and my mil, who is only slightly more successful at gardening than I am, told me it actually wasn't enough, so I watered them some more. It was right before we went on a weekend trip and I made sure everything I had was well watered. I came home and they were dead, dead, dead. The roses are doing great, btw.
So, are their water requirements just a lot different than the roses'? Are they easy to over water? The thing about asking my mil is that if I make a mistake, it's almost always to under water, hers is to drown things; but I tried slacking off and also being more generous.
I have some other ones in a different location, that gets more early sun and the flowers are doing great but the foliage is kind of ugly.
I am in the process of replacing the dead ones with verbena. Any advice regarding that choice?