Here is a list of American sunflower gardening resources, along with descriptions and websites where you can find more information and guidance. While there are many more resources available, these should be a good starting point for your sunflower gardening journey.

1. National Garden Bureau:
   The National Garden Bureau offers a wealth of information on various gardening topics, including sunflowers. They provide tips, guides, and resources for growing sunflowers.
2. Burpee:
   Burpee is a well-known seed company that offers a variety of sunflower seeds and gardening resources. Their website includes growing guides and product information.
3. University of California Division of Agriculture and Natural Resources:
   The University of California provides research-based information on sunflower cultivation. They cover topics like soil preparation, watering, and pests.
4. The Spruce:
   The Spruce’s gardening section includes articles on growing sunflowers. They offer step-by-step guides, care tips, and recommendations.
5. American Meadows:
   American Meadows is a great resource for sunflower seeds and wildflower gardening. Their website offers information on different sunflower varieties.
6. HGTV:
   HGTV provides gardening ideas and tips, including those for sunflowers. Their website features articles and videos on sunflower gardening.
7. National Sunflower Association:
   While mostly focused on commercial growers, you can find lots of information about nutritional benefits of sunflower seeds, tips on feeding the birds, and even a downloadable coloring book for big sunflower fans.
8. Gardening Know How:
   Gardening Know How has a section dedicated to sunflower care. It includes articles on planting, maintenance, and troubleshooting.

These resources should provide you with a solid foundation for growing sunflowers in the United States. You can explore their websites for detailed information and tips on sunflower gardening.