The name "osage orange" is misleading because this unattractive fruit, often called "hedge apple" or "monkey brains," is actually a member of the mulberry family. Wild osage oranges line the roadways in parts of Oklahoma and Texas, but you can grow them in other parts of the country---they are known to exist as far away as Virginia. The best way to locate seeds is from a fruit that has fallen to the ground. Fall frosts will cause them to become mushy, which is the best time to pick seeds from the fruit---if you can beat the squirrels to them.
Cut open a fallen fruit and scoop out the seeds. Soak them for one week in warm water. Give them fresh water daily to help prevent the seeds from fermenting.
Plant one seed about ½ inch deep in each small pot. Make sure you use pots with drainage holes and use a sandy potting soil, such as the kind that is used for cactus.
Move your pots to a sunny spot and keep them well watered until you see germination begin. After germination, water your seedlings when the soil just begins to become dry.
Plant young trees in their permanent outdoor location when they are about 1 foot tall. If you want to create a hedge, plant them 5 feet apart in an area that gets full sun and into which you have put a bucketful of compost into each planting hole.