Last fall a local nursery unloaded 10 tarragon plants on me. (Ed. note: NOT pictured above.)They are doing great, and I would love to use them in my cooking. I read however, not to bother using any tarragon not labeled "French." The tags for these plants don't specify, which makes me worried they are non-tasty. How can I tell if they are French tarragon?First of all, try a search over at GardenWeb, a great source of info on all things herb and garden.
• Russian Tarragon and French Tarragon at GardenWeb
Also, try looking up your herb on Flickr:
• French tarragon photos at Flickr
In the end, regardless of what kind of tarragon you have (Russian, French, Mexican) you are stuck with some good plants, no matter what. Yes, French tarragon is to be preferred for some recipes, but all types of tarragon are actually very useful and tasty. Some are just stronger than others, so you have to taste and judge whether they are right for a recipe.
Russian tarragon does, however, tend to lose its flavor as it matures, so that is the least preferable variety. It is, unfortunately, very commonly sold at nurseries.
Also, Mexican tarragon (Tagetes lucida - pictured above) is a pretty fabulous perennial plant. It's hardier than French tarragon, and although the leaves have a stronger taste (more like anise) they are all edible, as are the pretty yellow flowers. The flowers are somewhat similar to marigolds, which is why this plant is sometimes sold as Mexican marigold. It's also a great companion plant, attracting bees and repelling unwanted insects.
Our suggestion, then, is mainly just to taste the plant's leaves and judge whether you'd like it in a dish or not.