I've seen a few questions with the
Garden tag. Do we need this tag? What does it mean and when is it appropriate to use it?
I don't think the tag is helpful... if you're looking for culinary uses for a garden item (like the Roses question) that isn't what most people think of as an edible item, you could still tag the question as that item (flowers, in this case).
"Garden" could apply to endless items one can grow in their own garden. It doesn't really narrow anything down.
And if the question is about how to grow an item, well, it's more of a horticulture question, and is probably off topic.