A lot of times people will make a trip to their local garden center or nursery when things are in full bloom and at their prime and make all kinds of impulse purchases. That can wind up being bad news for both the customer and the garden center when it fails to live and thrive. Customer returns to said garden center absolutely livid. Garden center replies with a dumbfounded look and a shrug because they haven't been trained to know why things die. We at Mitchells try to train all employees in proper plant care. Then ensues the questions, which just fuel the fire. Did you water it? "Of course I watered it, do I look like an idiot?" Did you fertilize it? "Yes!" Pay attention to when you watered it and how much. We recommend watering twice a week in the summer, if you don't get a good soaking rain of at least 1/2". Rain gauges are cheap, so buy one. If you go on vacation, be sure someone waters it while you are gone. Water at least 3 times, letting the water soak into the ground between waterings, soaking thoroughly. Fertilize in spring with a timed release fertilizer and again in July to get plants off to a good start.
Now keep in mind this was probably purchased in the middle of May and now it is mid-August. If all was done correctly and the poor plant still died, there is a good chance it was not intended for your zones heat or drought. That is why it is always a good idea to inform yourself about what will and what won't tolerate the temperatures and weather conditions in your area. Don't just look at the colors on a map and think you know all you need to know. That is only a broad overview. The conditions in your area of your zone can vary widely from another area in the same zone. For instance, if you live near a creek, you may see frost sooner than those who do not as the relative humidity is higher near the water. Or, if you live close to the bottom of a mountain you may be sheltered from a lot of the colder temps or winds and it may warm faster for you. Elevation, natural water sources, forest cover, and so many other things you don't think about are factors in when you should begin your garden each year.
If you are the journaling type, you may want to keep a journal from year to year. Make notations on temperatures, weather patterns, first and last frosts each year and compare them to the generalized planting guides that the USDA provides. With that information, you could then share it with your community or even start a community gardening club and exchange your yearly information. It is also a good idea to stay informed about pests or diseases in your area. You can usually check in with your local extension office to get advice on these issues. Each county has its own extension agent, so go to the website to find out who your agent is.
Zone 7 is a temperate zone with generally mild summers and equally mild winters. That sets us up for success with a lot of plants that will survive our summers and winters. However, it also keeps us out of growing a lot of plants too. Tropicals are annuals here and on the flip side, there are a lot of trees that won't live here that thrive in the northeast.
Either way, get familiar with your zone. Learn all you can about the climate and make the most of the plants that thrive here. think native and you will never go wrong.