Rue Ruta graveolens is an interesting plant, and has had the attention of humans for centuries. It originated in Southern Europe. Used by the Romans for medicinal purposes, and the rest is history. One can plant around the house as defense against witches, and the plague. Used to help with various maladies from vision to epilepsy.
The leaves of the plant have a distinct smell, and are used in sachets or just strewn around to repel fleas and other pests. (There could be a relationship with the flea repellent and the plague though cause/effect not known at the time). It is also said to be a good companion plant to stave off some of the pesky insects in the garden.
As I usually have starts of rue at the farmers market, have had some interesting conversations. Yesterday a young woman who is a fellow vendor had to get one., She is from Peru, and said one needs it to help protect the home. (she and her hubs just bought a house). We agreed the plant must have been introduced into Peru by the Spanish, several centuries ago. Then another woman who is a regular there had to have one. She is multi-lingual, from Europe, spent time in S America, now here. Last year a young fellow stopped and checked the plants. Paused at the rue, and said his Grandma would put sprigs behind her ears for earaches. Grandma is in Mexico City.
I like it as it has pretty foliage with a blue-grey tinge, is near evergreen, needs little attention. It is also a host plant for black swallowtails (though mine usually go for the parsley as there is so much). I also haven't been bothered by witches or the plague lately, so it must be helping to protect the house.