Azadirachta indica, or Neem Tree, is an evergreen tree native to Southeast Asia. The tree will reach up to 100 feet (~30 m) tall with limbs reaching half as wide. The shiny dark green pinnately compound leaves are up to 12 inches (30 cm) long. Each leaf has 10-12 serrated leaflets that are 2.75 inches (7 cm) long by 1 inch (2.5 cm) wide. All parts of the tree have been used medicinally for centuries. It is widely used in toothpastes, soaps and lotion today, as well as being a biological insecticide. The tree grows well in containers, where its size is easily controlled by container size and selective pruning. Neem trees are hardy outside in USDA zone 9-11.
Blooming: In the greenhouse, the tree blooms in mid to late spring, producing small white, honey-scented flowers in terminal panicles.
Culture: Azadirachta indica will grow in full sun to partial shade, growing best in a well-drained soil mix. In the greenhouse, we use a soil mix consisting of 1 part peat moss to 2 parts loam to 2 parts sand or perlite. Even though the trees are very drought tolerant in nature, they are less so in containers. Trees should be well watered and allowed to dry slightly before watering again. They are fertilized on a monthly basis during the growing season with a balanced fertilizer. During winter months, water should be restricted and fertilizer avoided during this period. All repotting and pruning should be done at this time.
Propagation: Azadirachta indica is propagated from cuttings, layers, removal of suckers and by fresh seed. Fresh seeds germinate readily in 14 to 21 days at 68 to 72° F (19-22° C).
Azadirachta indica was featured as Plant of the Week May 27-June 2, 2005.
Guide to Past Plants-of-the-Week:
Cal's Plant of the Week was provided as a service by the University of Oklahoma Department of Microbiology & Plant Biology and specifically the late Cal Lemke, who used to be OU's botany greenhouse grower and an avid gardener at home as well. If the above links don't work, then try the overview site. You may also like to look at the thumbnail index. ©1998-2012 All rights reserved.