There is are still plenty of Yarrow flowers around on roadsides and spare land attracting insects.  It is attractive with clusters of white, flat-topped flower heads with many tiny individual flowers and appears from June to November.  Sometimes some of the flowers are pink as in this photo.  Cultivated garden yarrow flowers can also be  red or yellow.  Its latin name of Achillea millefolium literally means “thousand leaved” and represents the leaves which look feathery and there appear to be a thousand tiny flowers on the flower heads od each plant. 
Yarrow has been used in herbal medicine and for making herbal beers and ales in many countries. There are many folklores attached to it. including
In Greek mythology, the herb Yarrow was considered so powerful it was believed to bestow immortality on those who bathed in its waters. According to legend, Achilles was one such hero, having been dipped in the Yarrow-laced water of the river Styx by his mother when he was a baby. Alas, a spot was missed – his so-called Achilles heel – which would prove to be his fatal weakness in battle.
Hanging yarrow above doorways or strewn on the doorstep supposedly warded off malevolent spirits and hung above a bed would be a protection against various illnesses.
Before going on a journey ten stalks of yarrow would be picked and nine kept with the tenth thrown away as a tithing to the spirits, then if nine were put under the right heel, evil spirits would have no power over the traveller.