Weed Calendar
    
   
    Yellow bluestem
    
   
    Bothriochloa ischaemum
    
   
    Fall
    
   A fast-spreading perennial grass that is very hard to eradicate once established. A state of Arizona class B noxious weed. Photo: Michelle Villafranca, Fort Worth Nature Center & Refuge, Bugwood.org  
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    African sumac
    
   
    Searsia Lancia
    
   
    All Year
    
   An evergreen tree introduced for landscaping that has escaped into the wild. A state of Arizona class B noxious weed. Photo: Dan Beckman 
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    Giant reed
    
   
    Arundo donax
    
   
    All Year
    
   A perennial giant grass that clogs up waterways and guzzles water. A state of Arizona class B noxious weed. Photo: Karan A. Rawlins, University of Georgia, Bugwood.org 
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    Spotted knapweed
    
   
    Centaurea stoebe
    
   
    All Year
    
   A biennial or perennial flowering plant that grows in higher elevations in our area . A state of Arizona class A noxious weed. Photo: Rob Routledge, Sault College, Bugwood.org  
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    Onionweed
    
   
    Asphodelus fistulosus
    
   
    Winter/Spring
    
   An attractive flowering plant that can take over rangeland and grasslands. Both a state of Arizona class B noxious weed and a federally listed noxious weed. Photo: John Ruter, University of Georgia, Bugwood.org 
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    Ripgut brome
    
   
    Bromus diandrus
    
   
    Winter/Spring
    
   A winter annual grass that favors riparian areas and produces seed heads that can harm livestock and pets. A state of Arizona class B noxious weed. Photo: Joseph M. DiTomaso, University of California - Davis, Bugwood.org  
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    Stinknet
    
   
    Oncosiphon pilulifer
    
   
    Winter/Spring
    
   A winter annual with distinctive yellow flowers that is spreading at an unprecedented speed. A state of Arizona class B noxious weed. Photo: Sue Carnahan 
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