It has several religious uses including being used to spreinke holy water which gives it the name "herb of Grace" in some circles.
A member of the citrus family, it is an evergreen perennial with bluish-green leaves that grow in groups of six or seven off the semi-woody branches. The mature plant reaches about 2 1/2 feet tall. The leaves smell bitter and medicinal when cut or crushed. Rue produces many small four-pedaled flowers in mid- to late-summer. The foliage has an almost lacy look to it, although the leaf sections are not thin and pointy but rounded.
Rue is a dangerous herb that can cause powerful cramps, hallucinations and twitching. Even a small amount of contact will cause photo toxiicity (an ultra sensitivity to the sun) leading to severe burns and blisters.
They have an attractive and showy flower that contracts well with blue or purple flowers on surrounding plants. From late spring to fall rue bears clusters of bright yellow 5-petal 1/2 diameter flowers with a dimpled green center. It dies not have an attractive smell, however. The flowers will turn into hard green seed-heads that dry into brown husks and open to reveal and drop many tiny black seeds.
There is a myth that Rue will thrive if you steal it from a neighbor. If you decide to grow it by division, you will need to wear gloves, as many people have a reaction to the herbs essential oils.
This herb provides a sharp, spicy, and mildly bitter flavor and is used in some sausage meats served in the Middle East, such as merguez. In times past, Rue was believed to have many medicinal qualities due to the alkaloids, flavonoids and the volatile oil it contained. However, medical experts now believe that there are too many risks with the use of this herb and thus urge caution when consuming it, especially in large quantities. It is considered to be a poisonous plant.
This post was updated in Janaury 2017 with new photos and information.