Phormium tenax ‘Platt’s Black’ (New Zealand Flax)

An evergreen plant with deep purple sword shaped leaves that over time can develop into a 120 x 120cm clump. Please contact us for stock availability and sizes.

Hardiness traffic light amber

Hardiness level Amber

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An evergreen plant with deep purple sword shaped leaves that over time can develop into a 1.2 m x 1.2 m clump. With a long hot summer to lean into, it will produce a dramatic spike of red flowers.

Deepest purple-black plants are highly desirable, and we get quite excited about this one. We love it in masses, in great dramatic swathes or as blobs of exotic highlighting in a mixed planting scheme.

Particularly striking as an architectural focal point in a border brimming with flowers, its graceful plummy onyx leaves are a splendid contrast to chalky blue, pink, or pale yellow flowers. In a mixed border of evergreens and shrubs, we like to plant it with rolling mounds of Hakonechloa macra for a fun meeting of complementary, arching forms. Black and green at first, standing well back in autumn to marvel at the magnificent colour-play between the pairing as the Hakonechloa turns a rich yellowy orange. Purple and gold: bold and perfect.  

This plant is best in full sun and seems perfectly happy on any moist but well-drained soil, in any aspect. Hardy but may benefit from some protection in a cold winter. Will grow well in a pot as long as the pot is big.


N.B. When clipping several plants with the same tool, have a bucket containing a 5% bleach solution and swish your blades around for 30 seconds between plants to sterilise them. This will help avoid the chance of cross contamination of disease.

As with all woody plants, plant high, exposing as much of the taper at the base of the trunk as possible. Allowing soil to accumulate round the base of a tree can be fatal. Keep very well watered when first planted.


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