Plant in full sun to light shade. Can tolerate fairly dry conditions (coastal) but looks best with occasional to regular irrigation. Cold hardy to 15-20° F and possibly root hardy below these temperatures but with severe foliage damage unless protected.

'Black Adder' is a spontaneous tissue culture mutation of Phormium cookianum 'Platt’s Black', a cultivar we previously grew that was selected by Mr. Graham Platt of Platt's Nursery in Auckland from seed collected from Phormium 'Black Knight'. 'Black Adder' was discovered by Pat Fitzgerald of Fitzgerald Nurseries in March 2003 at in a laboratory in Enniscorthy, Ireland and grown on for evaluation at Mr. Fitzgerald's nursery in Kilkenny, Ireland. This sport has glossier foliage of a deeper blackish purple as compared to the dark brown color of the parent cultivar 'Platt’s Black'. 'Platt's Black' is sometimes listed as a Phormium cookianum cultivar and we often see 'Black Adder' listed this way as well but Peter Heenan treated 'Platt's Black' as a hybrid in his 1991 Checklist of Phormium Cultivars, published by the Royal New Zealand Institute of Horticulture, so this should hold true of this sport from that plant as well.

This plant received U.S. Plant Patent 20,451 on November 3, 2009 and was introduced in the U.S. by Anthony Tesselaar Plants of Melbourne, Australia. This has been a good plant but problems getting the laboratory plants rooted out has caused shortages and we also saw a fair amount of green foliage sporting on this cultivar much like we saw on the parent plant 'Platt’s Black', so we only grew it from 2011 until 2015. 

The information displayed on this page about Phormium Black Adder ['FIT01'] PP20,451 is based on our research conducted about this plant from books in our nursery library as well as from information that is provided by reliable online resources. We also have included our own observations made about it as it grew in the nursery gardens and other gardens visited, as well how the crops of this plant performed in the containers when we had them in our nursery field. We also include comments received from others and welcome hearing from anyone who has information about this plant, particularly if it includes cultural information aiding others to better grow it.