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Thursday - April 07, 2011

From: Austin, TX
Region: Southwest
Topic: Shrubs
Title: Knife Acacia or Shrubs for Austin
Answered by: Brigid & Larry Larson


Hello, Do you know if knife acacia is a suitable plant for North Austin? Does it have sharp leaves or thorns? How large and full does it get? We are looking to replace our existing pampas grass plants.


Mr Smarty Plants approves the removal of Pampas Grass, since Cortaderia selloana, commonly known as Pampas Grass, is a tall grass native to southern South America, and is an introduced species.   On the other hand, Acacia cultriformis (Acacia knife) is native to Australia.  It’s named that because it’s leaves have an unusual triangular shape, like a knife blade or shark fin.  Reports varied in the 12-16 foot region for both height and width.  So, we're not supportive of that selection either, as not only is it non-native, but it is also listed in weedwatch as a potentially invasive species.  

  From your description, I would expect that you are looking for a tall grass or mid-height shrub.  The Wildflower Center mission is to encourage the use of native plants and there are many to choose from.  In my search I found three different varieties of Sumac:  Rhus virens (Evergreen sumac), Rhus aromatica (Fragrant sumac), and Rhus glabra (Smooth sumac).  Other attractive species include Erythrina herbacea (Coralbean)Eysenhardtia texana (Texas kidneywood) and Bauhinia lunarioides (Anacacho orchid tree).

Rhus glabra
                      Eysenhardtia texana                  Erythrina herbacea  

  These were found using the recommended species page for Central Texas and looking at the shrubs 6’-12’ in height.  Depending on what you are actually looking for, you could review these or other recommendations and find some attractive and suitable plants to replace the Pampas grass!


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