According to Bob Frazee, retired University of Illinois Natural Resources Educator, hedge apples are produced by the Osage-orange tree (Maclura pomifera), which is commonly grown throughout Illinois. The Osage-orange is a member of the Mulberry Family and is commonly called a hedge tree.
As early-American settlers began moving west during the nineteenth century, many Midwest farmers found the Osage-orange tree to have many admirable qualities. According to Frazee, it is a tough and durable tree; transplants easily; tolerates poor soils, extreme heat, and strong winds; and has no serious insect or disease problems. Consequently, it was planted widely as a living fence because, when its thorny branches were pruned into a hedge, it provided an impenetrable barrier to livestock.
The wood is extremely hard, heavy, durable and shrinks or swells little compared to the wood of other trees. Thus, the wood is typically used for fence posts, treenails, furniture and archery bows. According to University of Nebraska researchers, dried hedge is highest in BTU's of dried wood from native trees when used as firewood. However, cautions that burning hedge does result in considerable sparking, so a protective screen or shield needs to be placed between the fireplace and the room.
However, Frazee reports it is the fruit of the Osage-orange that most individuals find intriguing. Although kids take enjoyment in throwing them, they are usually considered a nuisance in the home landscape.
Many people purchase hedge apples believing that hedge apples can repel or control insects, spiders and even mice in their homes, basements and garages. The use of hedge apples as a pest solution is often communicated as a folk tale complete with testimonials about apparent success. Unfortunately, there is an absence of scientific research and consequently, no valid evidence to confirm the claims effectiveness. According to Frazee, a few years ago, toxicologists from Iowa State University extracted compounds from hedge apples that were found to repel insects when concentrated. However, the scientists reported that natural concentrations of these compounds in the hedge apples were too low to be an effective repellent.
If you decide to pick hedge apples to check out their ability to control pests, or to use the fruit as a fall decoration, Frazee cautions that it is important to wear gloves. The milky juice present in the stems and fruit can cause irritation to the skin.