I heartily agree with the ease of growing Rose of Sharon. I'm in the same zone as you so that may be the reason we agree. I bought a new color at a garage sale last summer, growing in a six inch pot. I had a serious illness slow me down some and never got it in the ground or even watered it much. This spring it burst forth with new leaves and is now growing in my yard. As I have moved house several times I always put one in and have yet to lose one. However, I can't keep Sweet Peas. I did buy a place with them already growing and didn't kill them but I have never got them to grow from seeds I have planted and I've tried many times. They always germinate and grow to a spindley vine but never show up the next year. I'm thinking back and I'm sure I've tried to start them at least five times. The ones I got when I bought a place were on the east side of a shed and had other things growing in front so I'm wondering if they like cool roots that are shaded like clematis does. This will be my first full year here in this new place so I'm going to try again. As to the other plants you consider easy, I agree completely. Those are the old tried and true flowers of my grandmother's gardens. There are several others like Oriental Lilies that fall in the easy catagory. Mums and Cannas are also very easy to grow here. I was going to say someone could put together a lovely garden with the ones you list and then thought that I actually always have. They were the mainstays of every garden I've ever planted and that includes the new garden I have here.