A savanna is described as a grassland with shrubs and trees. The weather is warm all year long with the rainy season in the summer and dry season in the winter. The African savannas in East Africa and the Serengeti Plains of Tanzania have little surface water in the dry season. The plants have adapted by developing long roots that go deep in search of ground water, leaves that fall off to help save water and trunks that can store water during the wet season for the dry season ahead.
Baobab (Adansonia digitata) is also called the dead-rat tree, bottle tree and monkey-bread tree and is a member of the bombax family. The baobab is a deciduous tree that grows from 35 to 70 feet tall with a trunk dimension of up to 35 feet and branches that spread out as far as 100 feet. The extra-large trunk serves as a water reservoir in times of drought. The tree produces palm-like leaves growing in clusters at the ends of the branches, The leaves fall off during the dry season. When the dry season is over, the tree produces white-purple flowers that measure 4 to 5 inches across and 4 inches long, opening only at night. The flowers are followed by velvet-covered fruits that grow up to 12 inches long. Plant baobab in full sun and a soil that is dry to moist and well drained. Baobab is hardy in only the hottest, tropical areas of the United States, USDA hardiness zones 10 through 12.
River bushwillow (Combretum erythrophyllum) is also known as the hiccup nut and grows up to 20 feet tall with green leaves that measure about 3 inches long and 1 inch. The leaves turn yellow in the fall and red in the winter. The plant gets the name hiccup nut from the fruit, which is toxic and causes continuous hiccups if ingested. River bushwillow grows along the rives and streams in its natural environment and does well in a soil that is moist and well-drained to wet. The tree is hardy as far north as USDA hardiness zone 8.
Umbrella thorn (Acacia tortilis) is a shrub that grows to 6 feet high and 6 feet wide or a tree that grows to 50 feet tall and 100 feet wide, depending on the growing conditions. The plant produces thorny branches; compound leaves made up of hundreds of tiny leaflets; large seed pods that are a major food source for antelope, giraffe, elephant, monkeys and baboons; and fragrant cream-white flowers that grow in clusters of up to 400 at the tips of the branches. The tree is very adaptable, being able to survive temperatures as high as 122 degrees F during the day and below 0 at night and in areas with very little rainfall.