Acacia bonsai - Africa's pride!

Acacia in the Pierneef open umbrella style.

The following information has been copied from

http://www.zululandbonsai.co.za/

(Additional personal experience will be added in bold.)

The most successfully grown acacia for bonsai are:

• Acacia burkei – black-monkey thorn / swartapiesdoring.

• Acacia caffra – common hook thorn / gewone haakdoring.
• Acacia erioloba – camel thorn thorn / kameeldoring.
• Acacia galpinii – monkey thorn / apiesdoring
• Acacia karoo – sweet thorn / soetdoring.
• Acacia nigrescens – knob thorn / knoppiesdoring.
• Acacia robusta subsp. clavigera – narrow-pod robust thorn / brakdoring
• Acacia robusta subsp. robusta – broad-pod robust thorn / enkeldoring.
• Acacia sieberiana var.wookii – paperbark thorn / papierbasdoring
• Acacia senegal var. rostrata - Driehaakdoring
• Acacia erubscens- Blouhaak

Roots – Most acacia have a tap root system which is not conducive to bonsai cultivation.  Shortening the tap root over a period of 2-4 seasons will force a number of adventitious roots to develop. In time, this will produce a workable flat root system. Although good surface roots are rarely formed by acacia. Pieter du Plessis is experimenting on using a washer to layer of the taproot on younger trees - the reuslts are very promising. After removing the dead taproot he is planting the trees on tiles.
Bark – Most acacia bark is rough and has a tendency to flake.  The exception to this is Acacia karroo, which has fairly smooth bark when young.
Trunks – Acacia trunks are usually flexible and single when young but at a later stage split into low, heavy branches.  Healing is relatively easy if the tree in encouraged to expand.  Pruning back will, in most cases, result in a crop of new branches. Tapering may be problematic as the trees carry only a few sparse branches at a time.
Branches – The branches are often mistaken for multi-trunks due to their size and the fact that ramification is poor.  The branches are known to weaken if they are grown in a descending manner.  It is therefore in the trees’ best interest that it is treated as it is in nature with a short trunk and low, ascending branches.  There should be no evidence of a definite apex, but rather a crown formed by a multitude of branch ends.
Leaves – The species has difficulty in forming a large number of small branches, but this is compensated for by compound, bipinnate leaf formation.  Each branch bears a long leaf stalk and a multitude of leaflets which take the place of fine twigs.

In January 2014 I took these pics of an Acacia with an amazing nebari - the biggest nebari I have ever seen on the species:

20cm high Acacia senegal var. rostrata 2 years in training in the Pierneef style:

Pieter du Plessis visited our Kai on 20 April 2013 and did a talk on Acacia. Here are some of the trees he brought along:

White Monkeythorn:

 White Monkeythorn:

 Black Monkeythorn:

 This Monkeythorn is 30 years in training and grown from seed:

 Black Monkeythorn 20 years grown from seed:

African Bonsai Styles
1. Baobab Style
2. Pierneef Style / Open umbrella Style
3. Flat Top StyleBushveld or Natural Style (Shizen-zukuri)

4. Bushveld or Natural Style (Shizen-zukuri)
Images courtesy of SA Bonsai