Bugweed - Solanum mauritianum
This invasive alien species is
present in the Mount Moreland Conservation area
Solanum mauritianum commonly known as Bugweed is a small tree or
shrub belonging to the potato and tomato family Solanaceae which is native to
Paraguay and Uruguay. It has
become a widespread invasive weed in many
countries including South Africa.
The plant has a life of up to thirty years,
and can grow up to 10 m tall. Its large greyish oval leaves are covered with felt like hairs. The flower
is purple with a yellow centre. It is tolerant of many soil types and quickly becomes established around plantations, forest margins, scrub and open land. Solanum mauritianum can form dense stands that
inhibit the growth of other species through overcrowding and shading.
All parts of the Solanum
mauritianum plant are poisonous to humans, especially the berries, handling the plants can cause irritation
and nausea. The dust from the plant can cause respiratory problems.
In our area birds in particular
the Speckled Mousebird (Colius striatus) eat the fruit and spread the seed far and
is a category 1 invasive plant
The best form of
invasive species management is prevention. If prevention is no longer possible, it is best to treat
the weed infestations when they are small to prevent them from establishing, controlling
the weed before it seeds will reduce future problems.
Small plants may be hand-pulled but mature
plants will re-sprout if they are cut down. Solanum mauritianum is easily killed with herbicides
applied as foliar, basal bark (painting herbicide onto the bark at the base of the trunk) or cut stump
applications. When using any herbicide always read the label first and carefully follow all instructions and
safety requirements. If in doubt consult an expert.
Cutting down, or removing seedlings by hand. The stumps of trees that have been cut down must be
treated with an application of herbicide otherwise they will rapidly re-sprout.
Solanum mauritianum is easily killed with
herbicides so very low dose rates, Glyphosate and triclopyr are registered in South Africa for foliar, basal stem or cut stump applications. A 0.5-1% solution of
either glyphosate or triclopyr mixed with water has given me good results.