Thursday, 23 January 2014

Acacia karroo one of South Africa's most beautiful and useful trees.

Acacia karroo (Vachellia karroo) Sweet thorn

This is one of South Africa's most beautiful and useful trees.

Acacia karroo

Acacia karroo which is native to southern Africa is a very attractive medium sized tree which due to it´s very wide natural distribution and tolerance to a wide range of soil types makes it suitable as a landscape tree in practically in any proudly South African garden. 

CMR Bean Beetle Mylabris oculata

In addition to being very attractive and suitable as a landscape feature it is also environmentally a very productive tree that attracts very large numbers of insects when in flower in particular honey bees which makes it an asset to any garden. When out of flower it is the host for a large number of insect species including butterfly many or which are a valuable food source for in particular birds. Acacia karroo is fast growing and flowers when very small so there is no need to wait for years to see and to experience the benefits of planting this tree.

Honey Bee Mimic Eristalinus taeniops

Acacia karroo is an integrally part of our country's history having been used for everything from raft-making to sewing needles and fencing for the houses of the royal Zulu women. The thorns were even used by early naturalists to pin the insects they collected!

Common Dotted Fruit Chafer Cyrtothyrea marginalis

A long running debate about the classification of Acacia was resolved at the 2011 Botanical Conference held in Melbourne.

The debate arose out of research over the past few decades which established that the two main groups of acacias (the African and Australian groups) were distinct and needed to be separated into different genera. The debate centered around the issue of which group of plants would retain the name Acacia, based on the following opposing views:

Those supporting the retention of the name Acacia for the African group argued that the genus was originally described from an African species, Acacia nilotica

Those supporting the retention of Acacia for the Australian group argued that the vast majority of species occurred in Australia and that reclassification of those species would incur considerable disruption and expense.

In the end the Australians were the winners and a group of African trees know as Acacias since ancient and biblical times now have other names.

Until the reclassification of the genus, Acacia had about 1400 species spread over five sub-genera.  Now Acacia is a genus of around 1000 species, most of which occur in Australia with another dozen or so being found in Asia.

Garden Fruit Chafer Pachnoda sinuata

What we have always known as Acacia karroo is now officially known as
Vachellia karroo a name that many including myself having voted against the name change will never accept.

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