New Zealand flax 'Sundowner'

Sun

Full sun to partial shade; leaf colour is usually strongest in sun. Shelter from cold, drying winds.

Water

Water regularly during establishment, then during prolonged dry weather. Established plants tolerate some drought, but container plants need more frequent watering.

Soil

Fertile, well-drained soil, including sandy or clay soils improved to prevent winter waterlogging. Tolerates coastal conditions.

Height

5-6 ft (1.5-1.8 m), sometimes taller in favourable conditions

Spread

4-6 ft (1.2-1.8 m)

Foliage

Evergreen. Long, tough, sword-shaped leaves with bronze-green centres and broad pink to rose margins; older leaves arch outward.

Growth

Moderate

Care needed

Low

• Deer resistant
• Drought tolerant
• Heat tolerant

Northern hemisphere months. In Australia, shift them by six.

Difficulty

Moderate

Toughness

Fairly tough

Pick your zone, country, light and whether you have pets.

1. Planting day

   1 ft (0.3 m)

2. After 1 year

   2.5 ft (0.75 m)

3. After 2 years

   4 ft (1.2 m)

4. After 3 years

   5 ft (1.7 m)

   full size

About 3 years to full size.

From a typical nursery size, at an average rate for this kind of plant. A rule of thumb, not a forecast.

Cats and dogs

Safe

Growth rate

Moderate

• Water deeply through the first growing season, allowing the soil surface to dry slightly between waterings.
• Apply a light dressing of balanced fertiliser in spring; avoid heavy feeding.
• Mulch around the clump, keeping mulch clear of the leaf bases.
• Use a large container with drainage holes and a free-draining potting mix.
• In colder gardens, move pots into a bright, frost-free place before hard frost and water sparingly over winter.

Pruning. In spring, cut dead or badly damaged leaves individually at their bases, taking care not to cut new shoots. Remove spent flower stalks near ground level; do not shear across the leaves.

Spring

Remove winter-damaged leaves and check the crown for soft or rotting tissue.

Spring

Plant once severe frost has passed, apply a light feed and renew mulch.

Late spring

Divide overcrowded clumps if needed, keeping several healthy leaf fans and roots on each division.

Summer

Water new plants and containers during dry spells; inspect leaf bases for mealybugs.

Late summer

Remove spent flower stalks if the plant has flowered.

Late autumn

Move containers under cover where hard frost is likely, and ensure outdoor plants drain freely.

• Use as a single architectural accent among low grasses and groundcovers.
• Plant in a large courtyard container where the pink-edged leaves can be seen closely.
• Combine with silver foliage and purple flowers in a sunny coastal border.
• Repeat widely spaced clumps along a broad path or gravel border, allowing room for mature arching leaves.

Garden styles it suits: Architectural minimal, Coastal, Modern, Modern courtyard, Dry gravel garden and Winter interest.

Plant it with: Lavender, Agapanthus, Blue fescue, Lamb's ears, Purpletop vervain and Rock rose.

Wildlife: Mature plants occasionally produce tall flower stalks with nectar-rich reddish flowers that may attract nectar-feeding birds and insects. It is primarily a foliage plant, so do not rely on it for regular flowering.

• Crown or root rot in wet soil: improve drainage, keep the crown clear of mulch and avoid standing containers in water.
• Frost damage: remove damaged leaves in spring and provide a sheltered position; use frost-free winter storage for pots in cold regions.
• Mealybugs hidden between leaf bases: inspect regularly, remove small infestations by hand and use a locally approved treatment if they persist.
• Brown leaf tips from drought or drying winds: water thoroughly when needed and provide wind shelter; damaged tips will not turn green again.

Not known to be toxic to cats, dogs, horses or people. The tough, fibrous leaves are not edible and may cause choking or digestive upset if chewed or swallowed.

Where it spreads. The parent species, Phormium tenax, is invasive in places including Saint Helena and the Azores. 'Sundowner' is not generally listed separately; check local restrictions and remove seed stalks near sensitive habitats.

• New Zealand flax 'Evening Glow' (Phormium 'Evening Glow')

  Usually shorter, with a greater proportion of red-pink across the leaf blade rather than the broad bronze-green centres typical of 'Sundowner'.

• Mountain flax (Phormium cookianum)

  Typically has softer, more drooping green leaves; its flower stalks bear hanging, twisted seed capsules rather than the upright capsules of Phormium tenax.

• Cabbage palm (Cordyline australis)

  Develops a woody trunk with leaves clustered at branch tips, while 'Sundowner' remains a basal clump of broad leaf fans.

Phormium comes from the Greek word for a basket, referring to the use of its strong leaf fibres in weaving.

Propagation. Divide established clumps in spring, separating rooted sections with several leaf fans. Division preserves the leaf colour; seedlings will not reliably come true to the cultivar.

Accepted botanical name

Phormium

Sources: GBIF (CC BY 4.0). The care and design notes are LandscapeGPT's own.