For hydrangeas it has something to do with the ph lvl in the soil if I remember right because we do get them to bloom in a blueish color.

To the original question. I grew up in Ohio and I have fond memories of spending a lot of time at Lake Erie growing up. We had a cabin at the lake in the gated cabin community with a private beach (Astabula area of Ohio). I know live in North Carolina. The past 10 years was in the Charlotte area and now I live at the coast. There is so much I can contrast, but not much I can compare. So many of the plants are different (really only the annual flowers and some of the large trees are the same), the weather is so very different. In Ohio I remember 4-5 months out of the year with snow on the ground, where in Charlotte we got 1-2 snow falls a year and the snow wouldn't last more than a day. Here at the coast if it snows everything totally shuts down. Ohio has 4 seasons of a real length, whereas here we have summer and winter with very little fall or spring. There are some things I prefer about the north and other things I prefer about the south. I must say I am so thankful that Sugar Maples will grow in the south, as they have always been my favorite shade tree. I bought one to Charlotte and it was doing very well when we moved. I'll be getting another one next spring to plant here from my parents. Although it does grow in NC it's not nearly as common of a tree here as it is up north.