The American sycamore, also called the American planetree or buttonball tree, is common in the eastern states from Texas to Nebraska, Iowa and Wisconsin, according to the U.S. Department of Agriculture Natural Resources Conservation Service. The cheapest way to obtain seeds is by harvesting the round seed balls from a mature sycamore in spring, when they fall to the ground after overwintering on the tree. If there are no sycamore trees in your area, you can buy seeds online or from some garden stores.
Break up the sycamore tree seed ball. The small seeds are oval-shaped and connected to fine hairs.
Plant five or six of the seeds about 1 inch deep in a 12-inch pot filled with potting soil in spring. Start the seedlings indoors or in a garden spot with no likelihood of frost. Keep the soil damp but not sodden.
Thin out the seeds when they have sprouted, leaving only three regularly spaced seedlings in the pot. Choose the seedlings that are growing best.
Scoop the seedlings out of the pot when they're around 6 inches tall. Take care not to damage the developing roots.
Dig a hole 6 inches deep and place the seedling in it. Fill the hole with compost, making sure the roots have a 2-inch layer of compost over them. Firm down the soil and water.
As the sycamore can grow to 100 feet, choose an open spot to plant your seedlings.
Some people experience an allergic reaction to the spores when the seed balls break up and disperse in the air.