if you ever cut the yarrow, the stalks of Achillea millefolium can be
used for throwing the I Ching...Chinese divination method..
http://www.tryskelion.com/ichstick.htm
http://www.eheart.com/yarrow/
http://www.bbc.co.uk/dna/h2g2/A647840
http://www.championtrees.org/yarrow/yarrow.htm

we used to sell these along with the I Ching book.

all your plants sound lovely...you must send us pictures!!