The African Tulip tree is well known to many with its bright and beautiful flowers accompanied by large pods that split open to spread light and papery seeds. Despite its beauty the tree is regarded as a significant environmental weed in Queensland and also said to be a “sleeper weed” in northern New South Wales. The tree presents such a threat that is has been listed on the Global Invasive Species Database and is considered to be one of the top 100 most invasive alien species in the world.
Native or Exotic?
Origin of Tree
Native to tropical western Africa
Family of Tree
The African Tulip tree presents a severe danger to native stingless bees as they are drawn to the flowering tree to collect pollen that is in fact fatally toxic to the native bees. This has caused whole colonies and hives to be wiped out in Northern New South Wales and other regions. This can be observed by looking into the mouth of a picked flower where you can see groups of bees either dead or moving around in a “drunken” manner.
Beyond the threat to our native fauna the tree can also present dangers to people if planted near walkways and other routes of travel. Both the flowers and the pods that birth them can drop onto the ground and cause the surface to become very slippery which can lead to injuries and public liability.
Flowers and Fruits
The flowers of the African Tulip Tree are its most distinctive feature. They present with large, vibrant flowers arranged in dense clusters at the tips of the branches. Each flower stems from short stalks that are covered in brownish hairs and they come from large horn shaped structures called a calyx tube. The tubes are brown and angle upwards and people can often be seen popping them open as they are full of liquid. The flower is tubular, like a tulip flower and has a large mouth that can measure 7 cm across. Each flower sports four stamens with large dark brown anthers that rest on stalks about 5 cm long.
Flowering occurs at all times of the year but usually peaks during spring time. They have large, elongated pods that encapsulate their seeds. These pods turn from green to brown as they mature and when they are ready split open and release up to 500 seeds. As the seeds are very light and are surrounded by a thing translucent membrane they can be carried wide and far from the original tree and further spread the species.
Stems and Leaves
The branches are thick and marked with small whitish spots known as lenticels. While young the branches can range from being almost hairless to have a sparse covering of smaller hairs. The large leaves are compound pinnate with 7-17 leaflets and are usually appositely arranged along the stems and rest on stalks up to 6 cm long. The new leafs are oval in shape and have a sparse covering of soft hairs.
Reproduction & Dispersal
The shape and style of the seeds of the African Tulip tree are the most common source of their propagation. They are light and often released from a significant height. This means their seeds are carried far and wide by not only winds but also by water if the tree happens to be growing along a waterway.