Vitex Negundo Incisa. Explorer, Frank N Meyer found Vitex Negundo in Shantung, China. Mr. Meyer describes Vitex Negundo as "a sage which may prove to be a good plant for the arid Southwestern states. It is able to resist alkali remarkably well. The Chinese use it for basketry manufacture, taking the annual shoots for this purpose. It has pretty blue flowers and is diligently visited by all kinds of bees, and as such it might be grown in gardens as a semi-ornamental shrub. It grows, when left alone, up to 20 feet tall."
H.B. Parks, in a letter to Frank C. Pellett, author of American Honey Plants, stated that it "makes a wonderful growth and that it is a most remarkable honey plant" (observations made in Texas). However, Vitex agnus-castus, though it blooms profusely, is not much value to bees.
So when it is stated that Vitex agnus is an improved selection of Vitex Negundo is it really? Vitex agnus has been "improved" for larger, showier flowers and there is no doubt that bees do still visit those flowers however their nectar yield is not the same had it been Vitex Negundo.