The depends on where you garden and which perennial wildflowers you are interested in. The best way we know of to go about solving that problem is to go to our Native Plant Database and, using the Combination Search about the middle of that page, search on North Carolina for state, herbs (herbaceous blooming plants) for Habit, and perennial for Duration. You can follow each link to our webpage on that plant to find out its growing conditions, propagation suggestions, height, light requirements and see picures from our Image Gallery.When we searched that way, there were 991 plants that fit the specifications! So, we scanned through them looking for attractive wildflowers. You will note there were so many that we only got to "F", as they are listed alphabetically by scientific name.
From HGTV, Best Time to Plant Perennials:
"Early fall is a good time to plant larger sizes of perennials (if they are available) because the weather is cool and reduces stress on the top parts of the plants. The soil also stays warm and allows the roots to grow, helping the plants to get established in the landscape. In the spring when the plants come out of dormancy, they should perform better than if they were planted in the spring and asked immediately to bloom (in addition to rooting and becoming established). Note that smaller-sized plants from small pots may not root deeply enough to avoid heaving during the freeze-thaw cycles. However, planting larger plants in fall generally works well."
So, you see, we were kind of playing around with you, because we already knew that. But, in the course of answering your question, we introduced you to our Native Plant Database and taught you how to use it to find information about any native plant you are interested in. One further tip, if you want to be sure the plant you are interested in is native to your specific area, where you can be a little more confident of the soils, climate and rainfall the plant will flourish in, go to the bottom of the plant webpage and click on the link to the USDA Plant Profile on that plant. First you will get a map of North America with all the states where that plant grows natively in green, click on your state (North Carolina) and you will get a map with the counties of that state in green where the plant is reported to grow.