Hi if you wanted to propogate these for your nursery in the Waikato at how would you go about this and how quickly could you get large quantities for these to meet demand?
Easily grown from fresh seed and division of established plants. I don't know about how quick from seed or divisions - but would assume divisions would grow faster. For seed you need to watch out you don't harvest plants infected by Bauerago gardneri - an endemic smut fungus that attacks the inflorescences of Cyperus ustulatus - see http://naturewatch.org.nz/observations/1774884 for an infected inflorescence. Best I can advise.
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