Answer: Based on what you've mentioned, I think the troubles you've had may be due to your soil's pH. Azaleas need acidic soil (pH 4.5-5) in order to thrive, and marigolds prefer a pH closer to neutral (around 6-6.5). Have your soil tested locally bythe extension service, or use Burpee's home soil test. Addition of organic matter helps neutralize pH, and it sounds like, after all those years of effort, it's paid off! But garden lime can be used as a shortcut to "sweeter" soil.
Burpee offers varieties that do well almost anywhere, but if you are looking for those that are tried and true in your neck of the woods, Southern Exposure Seed Exchange (PO Box 170, Earlysville VA 22936; ph# 804/973-4703) is one source to try. Hope this helps!
Q&A Library Searching Tips