Trifoliate orange (Poncirus trifoliata) is widely referred to as bitter orange and/or hardy orange. It is naturalized in the U.S. from Pennsylvania but has spread to Florida and Texas. It’s a fairly tall deciduous weed at 8 to 30 feet tall. Some reports also say that it can grow to be 20-feet wide as well. It has a trunk that is shiny and quite thorny with stripes in alternating rows of green-and-white as well as many branches. The Trifoliate Orange weed’s shiny green alternating leaves have three leaflets, which help differentiate it from other weeds.
The trifoliate orange weed is closely related to true citrus trees and belongs to the same family (Rutaceae). Atop its many branches, there is generally a tangled crown of branches laden with thorns that can reach up to two inches in length. At Oklahoma State University, there are a number of Trifoliate hedges that are three-feet tall and impenetrable. They’ve been growing there for more than 50-years and have become so dense that people can walk on them.
Trifoliate orange weed was first noted in the Prince Nursery list in 1823 as the Poncirus. It didn’t garner any attention, however, until 1862, when the U.S. Department of Agriculture had been established, separating it from the Patent Office. A botanist/landscape gardener named William Saunders who lived between the years 1822 and1900 was hired by that department. He was the one responsible for popularizing hardy orange during the post-Civil War era.
Springtime for trifoliate orange brings slightly citrus-scented bright white flowers in clusters, making it look deceivingly pretty. It also produces golf-ball-size green fruit during the summer and early fall, however, it’s extremely bitter. In spite of that bitterness, numerous interesting recipes have been devised using the fruit of this weed.
In the fall, the leaves of the trifoliate orange weed drop to the ground, and the fruit turns yellow. Although it smells quite citrusy and fragrant, it contains mainly seeds and very little pulp. Any pulp that there is will be exceptionally sour, however, an innovative Tennessee nurseryman came up with a poncirus-aide recipe. It involves a barrel of sugar added to a barrel of water with just one single sour fruit. In addition, the fruit has been known to be used for making candied orange rinds and marmalade.
Under the right conditions, this weed spreads quickly, both via basal sprouts from its roots as well as dispersing of seeds by animals and can require removal as part of regular lawn care. When it becomes a problem along with other lawn weeds, getting rid of Trifoliate Orange weed means:
The thorns are quite treacherous, so wearing a long sleeve shirt, heavy pants and goggles could be necessary for protection.