Phormium Black Adder – Learn, Buy & Grow

Phormium ‘Black adder’, also called Black New Zealand Flax is a cultivar of the phormium genus with an astonishingly dramatic glossy, blackish-purple foliage.


This cultivar was discovered by Pat Fitzgerald but was created by a spontaneous mutation from a tissue culture of Phormium cookianum ‘Platt’s Black’. Its dark-purple leaves are glossy and grow upwards with an upright habit for up to 3 or 4 feet before they begin to arch at the tips.

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Additionally, these evergreen perennials are hardy and can survive temperatures between -6 and -9 degrees celsius. However, temperatures less than this will call foliage damage, and even if the roots are possibly hardy, they will need extra protection in frosty winters.

Phormium Black Adder

Phormium Black Adder

How to grow Phormium Black Adder

Black Adder is cultivated by division in early spring and is best grown in full sun or light shade in moist but well-drained soil. It looks best when grown in gravel gardens, in containers on your patio, or coastal, architectural gardens. You can prune out damaged and dead leaves in spring and watch out for phormium mealy bugs.

Where should I position Phormium Black Adder in my garden?

Like most other phormiums, ‘Black Adder’ is a sun lover and will thrive when placed in full sun or light shade with an east, south or west-facing aspect.

How tall does Phormium Black Adder grow and spread?

Black Adder is a slow-growing phormium plant but will reach its maximum height in 5 to years. It generally grows as tall as 3.2 to 4. Feet and a spread of equal diameter.

What kind of soil does Phormium Black Adder need?

Not generally picky with soil, Black Adder will thrive in chalk, sand, or loamy soil as long as it is moist and well-drained. The soil you select to grow your Black New Zealand flax can be acidic, alkaline, or neutral.

Other types of Phormium we cover:

Phormium Black Adder, Black Velvet, Bronze Baby, Colensoi, Cookianum, Evening Glow, Golden Ray,  Jester, Maori Queen, Pink Stripe, Platts Black, Rainbow Queen / Maiden, Phormium Sundowner, Phormium Tenax, Phormium Tenax Variegatum, Yellow Wave.

Further reading:

Where can I buy Phormium Black Adder? 

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