A paulwonia tree is also called a princess tree and the empress tree. In its native habitat of China, the paulwonia tree has been cultivated for several thousand years mainly for its wood which is used for timber, firewood and in making furniture. In the United States, paulownia is one of the more commonly planted fast-growing ornamental trees particularly when "instant shade" is desired. It produces striking trumpet-shaped, lavender to white, highly fragrant flowers that appear in clusters in early spring. You can propagate paulownia from seed at any time of the year but make sure you use seeds less than 4 years old.
Preparing Paulownia Seeds
Collect ripened seeds from a paulownia tree. Do this in September when the seed pods are light brown, and before they crack and open.
Place the seed pods into a canvas or burlap-type sack to air dry for about seven to 14 days.
Separate the paulownia seeds from the seed pods. One way to do this is to leave the seed pods in their burlap or canvas sack and then crush the contents, as suggested Donald H. Graves and Jeffrey W. Stringer with the University of Kentucky. You can gently crush the contents using a rubber mallet or hammer.
Place approximately 2 cups of sand and 2 cups of peat moss into separate containers, such as bowls or buckets. Dampen down the sand and peat moss until each is moist feeling when touched.
Place a 1 1/2-inch layer of sand in the bottom of a quart-sized lidded plastic container. Set the paulownia seeds on top of the moistened sand. Spread out about 1 to 2 inches of the moistened peat moss on top of the paulownia seeds. Set the lid on the container.
Place the container into your refrigerator that is set to remain at a temperature of between 38 and 40 degrees Fahreneheit. Keep the container in the cold storage for a minimum of two months. The cold storage will improve the germination rates of paulownia seeds. You can plant the seeds at any time after the allotted time has passed but do not leave the container in the cold storage for longer than four years since this will greatly reduce the viability of the seeds.
Planting Paulownia Seeds
Pour a seed starting mix into a seed starting flat until it is full.
Moisten the seed bed thoroughly. Dip the seed starting flat into a basin or tray that is holding about 1 to 2 inches of water, until the mix is well moistened.
Pick up a pinch of paulownia seeds between your thumb and index finger. Scatter the seeds randomly across the surface of the seed starting mix. Paulownia seeds require light to germinate, so do not cover the seeds.
Place a sheet of glass or a layer of clear plastic wrap over the tray. Put the tray under a florescent light fixture at a distance of about 10 to 14 inches away. Keep the tray under the light for 24 hours a day. Mist the tray with water every day. The ideal temperature should be no warmer than 85 F and no cooler than 70 F. Germination of paulownia seeds typically begins in about two to three weeks.
Remove the sheet of glass or plastic wrap once you see the seeds sprouting. Maintain moisture, but avoid over-watering. You can transplant the paulownia seedlings into 4-inch, 6-inch or 1-gallon pots once they each have a pair or two of leaves.