Check out this link
for a lovely poem by William Wordsworth entitled "Unvisited Yarrow".
The latin name is Achillea millefolium, but I always prefer the common or peasant names for plants as they are so descriptive. Nosebleed plant, Old Man's Pepper, Sanguinary, Soldier's Woundwort, Thousand-leaf , Thousand-seal, Arrowroot, Bad Man's Plaything, Carpenter's weed, Death flower, Devil's nettle, the Saxon word Gearwe, Hundred leaved grass, Knight's Milefoil, Knyghten, Noble Yarrow, Old Man's Mustard, Seven Year's Love, Snake's Grass, Stanchweed, Yarroway, the Dutch word Yerw. Many of these names come from old folk tales.
Yarrow derived its Latin name from the Greek hero Achilles, the son the Sea-Goddess Thetis and the mortal king Peleus. Thetis, attempting to make her son invulnerable, dipped him into the river Styx. But afraid to let the infant go completely, his ankles remained vulnerable where his mother had held him, the part that has become known as the 'Achilles heel'. She also wanted to make him immortal by the power of fire, but Peleus disturbed her in her ritual and so she fled back to her father, leaving the infant in Peleus' hands. Peleus gave him to Chiron, the centaur, who had a great reputation for educating young boys in the art of archery and healing. And so, Achilles went on to become one of the greatest warriors, but in the end he died of a mortal wound to his Achilles heel. Achilles used yarrow to staunch the wounds of his fellow soldiers, which is how yarrow became known as 'Militaris'.
In the Middle Ages, Yarrow was part of a herbal mixture known as gruit used in the flavouring of beer prior to the use of hops, hence its name 'Field Hops'.
The French name for this herb 'herbe de St. Joseph' is derived from a legend according to which Joseph one day hurt himself while working on his carpentry. The infant Jesus brought him some Yarrow, which instantly staunched the bleeding and healed his wounds.
In Britain girls used to determine whether their loves be true by sticking a yarrow leaf up into their nostrils while reciting the following rhyme:
"Yarroway, Yarroway bear a white blow
If my love, love me my nose will bleed now... "
Yarrow sown up in a little pouch and placed beneath the pillow was hoped to bring dreams of one's future husband if one recited the following charm before dozing off to sleep:
"Thou pretty herb of Venus tree
Thy true name be Yarrow
Now who my bosom friend must be
Pray tell thou me tomorrow."
The ancient oracle of the I Ching is traditionally cast with Yarrow stalks which are thought to represent the Yin and Yang forces of the Universe in perfect balance.
Yarrow was always part of the sacred 9 herb bundle. Originally a pre-Christian tradition, the church at first attempted to ban the gathering of herbs. But when it became apparent that this would be impossible to enforce, they sanctified the practice and even blessed the women's herb bundles in the church on Mary's Ascension day, the 15th of August.
Yarrow has also been used as a food, and was very popular as a vegetable in the 17th century. The younger leaves are said to be a pleasant leaf vegetable when cooked as spinach, or in a soup. Yarrow is sweet with a slight bitter taste. A special soup of herbs is the traditional dish for Maundy Thursday, the Thursday before Easter. This soup contained 9 holy healing herbs, one of which is Yarrow. This soup was believed to ward off all sickness and disease and dispel all evil influences for the whole of the coming year. Here's a recipe that comes close to what the original probably was: http://recipes.recipeland.com/recipes/recipe/show/Bavarian_Herb_Soup_Krautlsuppe_4397
So what is Yarrow good for? I'm not giving medical advice but it is supposed to be good for stopping the bleeding of wounds, healing menstrual issues, easing colds and flu symptoms and cleansing the body inside and out. Yarrow tea, salve, tincture, etc are all available or you can make your own as there are lots of recipes on the internet. Make sure you know your plant and realize that it can cause allergic reactions in some people. Do your homework.