This is Mexican tarragon. In my part of the country, it is a perennial. In colder climates, it would be considered an annual because it would freeze in the winter. This plant will get about this tall by the end of fall- about three feet tall- and it will have solid, golden-yellow flowers on it. It’s just a stunning garden piece by the end of the summer, into the fall.
Medicinally, it is a diuretic and it increases perspiration so it’s a cleanser. So it’s very delightful to use as a tea- as an herbal tea. So you can cut the leaves off and dry them, or use it fresh and make it just as you would mint tea, or any other tea, by pouring the boiling water into the leaves and letting it steep.