Kalopanax septemlobus, commonly known as Kalopanax or Prickly Castor-oil Tree, is a deciduous tree native to northeastern Asia. It belongs to the family Araliaceae and is the sole species in the genus Kalopanax. This tree can be found in regions ranging from Sakhalin and Japan all the way to southwestern China.
The Kalopanax septemlobus is characterized by its maple-like leaves and dark gray, ridged bark. Younger stems bear spines, and white flowers bloom in late summer, sometimes forming massive clusters up to 2 feet in size. This tree has a unique appearance - it is very open and rather coarse, with a vaguely round crown. It thrives in deep, rich soil and full sun. When mature, it makes an impressive shade tree.
Growing up to 30 meters tall, with a trunk diameter of 1-1.5 meters, this species of tree is noted for its spiny stems, with stout spines reaching up to 1 centimeter in length. Its alternate leaves are large and palmately lobed, resembling those of a Fatsia or sweetgum leaf. The lobes of the leaves vary greatly in shape, ranging from shallow lobes to those that are cut nearly to the leaf base.
In late summer, this tree produces large umbels of flowers, measuring 20-50 centimeters across, at the apex of a stem. Each flower has 4-5 small white petals. The fruit is a small black drupe that contains 2 seeds.
The Kalopanax septemlobus is commonly cultivated as an ornamental tree in Europe and North America due to its tropical appearance. Despite its tropical looks, it is highly hardy and can tolerate temperatures as low as -40°C. While it initially grows quickly, its growth rate slows down once it reaches around 40 years old.
In terms of cultivation, this tree can adapt to a variety of soil types, including light sandy, medium loamy, and heavy clay soils. It prefers moist soil and can be grown in semi-shade or no shade. It is also capable of thriving in acidic, neutral, and basic (alkaline) soils.
Overall, the Kalopanax septemlobus is a unique and attractive tree with a tropical appearance that is highly valued as an ornamental plant. Its resilience and adaptability make it a popular choice for gardens and landscapes. For more information on this tree, please visit http://plants.usda.gov.
