Most peony trees are grown from grafts because many peony trees don't produce seeds. To get seeds, the flower buds must be removed, causing the tree to grow smaller flowers that may produce seeds. Those seeds will not grow a peony tree that is true to the parent the way a graft does. This has made growing peony seeds popular among those who want to develop new peony varieties. Depending on the species, a peony tree may grow anywhere from 4 to 15 feet in height.
Place the peony tree seeds into a plastic bag that contains a commercial germination mix that doesn't contain soil. Moisten the germination mix and seal the bag.
Keep the bag in a warm place that is not in direct sunlight. Check the bag every week to see if the seeds have started to sprout roots. This may take three or four weeks or it may be a few months before the roots appear.
Place the bag into a refrigerator and leave it there for about three months at a temperature of about 40 degrees F once the roots get to be about 3 inches long.
Take the bag out of the refrigerator when a stem shoots begins to grow. If the weather is cold, plant the seed in a plant pot with some potting soil and use grow lights until the spring comes. Peonies grow slowly, so a 4-inch plant pot will contain a peony tree seedling through the fall and winter.
Plant the peony seedling outdoors if it is spring or summer. Choose an area that gets full sunlight and good drainage. Add some compost to the soil if possible. If you don't have any compost, try a granular fertilizer.
Fertilize your peony tree every fall with compost or in the spring with a granular fertilizer.