Paulownia kawakamii is just one variety of a set of trees known as "royal empresses." They are most notable for their fast growth--between 8 and 12 feet a year. The Paulownia kawakamii variety typically reaches between about 30 to 40 feet tall. The Paulownia kawakamii tree is also favored for its fragrant blue flowers with yellow centers, which adorn the tree six weeks each spring. To achieve the expected rapid growth of your Paulownia kawakamii tree, you must care for it, including giving it proper irrigation, especially during the first two years.
Sprinkle the roots with water if you received your Paulownia kawakamii bare-rooted tree in the mail, and then plant it in moist, all-purpose potting soil in a container with drainage holes. If your tree came potted and the soil is already moist, you do not have to water it yet. However, if the soil is dry, water it until the water seeps out the bottom, then dump out the excess water.
Keep your potted Paulownia kawakamii moist until you are ready to plant it outdoors. Water it only when the top 2 to 3 inches become dry. Always dump out the extra water after watering. It's best to keep your Paulownia kawakamii potted for at least two weeks and set in a partially shaded location to acclimate it to the outdoors prior to planting it in the ground. Plant before temperatures reach 90 degrees F.
Water your outdoor Paulownia kawakamii with about an inch or two of water after planting, and gently pack down the soil to get rid of any air pockets. Then continue to water it (under the entire canopy) with about an inch of water two times per week from spring until fall when rainfall does not meet this need, especially during the first two or three years when the tree is still young and growing rapidly.