Phormium

phormium

( FOR - mee - um )

At-A-Glance Information

These New Zealand native plants are known for their dramatic sword-like evergreen foliage and fan pattern. They are wonderful on hillsides, in borders, in containers, and near pools and other bodies of water. Once established, plants will produce spikes of flowers. These plants need full sun to partial shade and need little to regular water to perform well. Phormium plants are hardy down to about 20 degrees Fahrenheit. Use Phormium as drought-tolerant additions to the landscape, as focal points or specimens in mixed beds and borders, as privacy or wind screening, for erosion control on slopes, or in containers.

Phormium Species and Varietals

The genus Phormium is a member of the plant family Asphodelaceae and includes two species and many hybrids. Plants in this genus are closely related to those in Hemerocallis (Daylily), Dianella (Flax Lily), Kniphofia (Torch Lily), and Aloe. The best growing zones for Phormium are USDA hardiness zones 8a-11 or Sunset growing zones 7-9, 14-24, H1 and H2. For more information, see the species descriptions below. To find your zone, click here: Zone Map.

Phormium cookianum (Phormium colendoi) (Mountain Flax, Lesser New Zealand Flax, Coastal Flax, Hill Flax, Wharariki)
This species has drooping leaf tips; leaves reach 4-5 feet long and are 2.5-3 inches wide. Mature clumps of foliage reach 4-5 feet tall and 8-10 feet wide (or more, if given the space). This species is considered invasive in the United Kingdom. Choice selections are listed and described below.

'Black Adder'
To 3-4 feet tall and just as wide, with glossy burgundy-black leaves.

'Flamingo'
1-2 feet tall and wide, with leaves that have shades of orange, pink, light green, and yellow in them.

'Cream Delight'
Leaves have a broad central margin in cream and narrow green margins outlined in dark red.

'Tricolor'
Green leaves are margined with cream and red. Foliage blushes pink in cooler temperatures.

Phormium spp. Hybrids (Hybrid New Zealand Flax, Hybrid Mountain Flax)
This group of plants are crosses between Phormium cookianum and Phormium tenax, and have eye-catching foliage color. Leaves are generally between 1.5-2 inches wide. Cultivars are listed and described below:

'Apricot Queen'
3 feet tall and 5 feet wide, with 2-3 inch wide leaves. Foliage is light yellow with green margins and blushes with light orange in cool temperatures.

'Bronze Baby'
3-5 feet tall and wide. Leaves are deep red-brown and age to bronze. Leaf edges are orange and the midrib glows in the sun.

'Dark Delight'
4 feet tall and 8 feet wide, with 1-2 inch wide leaves. Leaves are dark red-brown with a thin orange midrib.

'Dazzler'
Slow growth to 3 feet tall and 5-6 feet wide, with twisting, arching leaves that are scarlet and striped with maroon.

'Duet'
Reaches 2-2.5 feet tall and wide. Leaves arch slightly and are lime green edged with creamy yellow.

'Dusky Chief'
Forms a dense foliage clump 3-5 feet tall and wide. Leaves are wine red with coral edges, 2-3 inches wide.

'Ed Carman'
Upright grower to 2-3 feet tall and just as wide. Foliage is bronze edged with light pink to white.

'Firebird'
Stiff, upright grower to 6 feet tall and 3 feet wide, with rose-red leaves that have bronze-green margins.

'Golden Ray'
4-5 feet tall, slightly arching. Leaves are striped green and cream and have red edges.

'Guardsman'
6-8 feet tall and just as wide; 3-inch wide leaves that are maroon with a bright red border.

'Jack Spratt'
1.5 feet tall and wide, with 1/2 inch wide leaves that are twisting and red-brown.

'Jester'
1.5-2.5 feet tall and wide, with rich pink arching leaves that have hints of orange in them. Leaf edges are lime green.

'Maori Chief'
('Rainbow Chief')
Robust grower to 6 feet tall and 6-8 feet wide, with green, rose-edged leaves.

'Maori Queen'
('Rainbow Queen')
3 feet tall and 4-5 feet wide. Bronze-green with wide coral-cream margins.

'Maori Sunrise'
('Rainbow Sunrise')
3 feet tall and 5-6 feet wide. Bronze-green striped foliage with pink-orange.

'Morticia'
To 3-4 feet tall and wide, with purple-black leaves.

'Pink Stripe' ('Pink Edge')
4-6 feet tall and wide, with grey-green foliage blushed purple. Margins are bright pink and get broader towards the base of the plant.

'Platt's Black'
This variety reaches 2-3 feet tall and has dark burgundy to nearly black leaves. Best in cooler climates.

'Sea Jade'
4-5 feet tall and 5-6 feet wide, with maroon to bronze leaves edged with lime green.

'Sundowner'
5-7 feet tall and wide, with 3-inch wide leaves. Olive to bronze-green foliage is striped with pink-red and with red edges. Undersides are grey-green.

'Sunset'
4-6 feet tall and wide with apricot to pink leaves that are striped with green.

'Surfer'
2-4 feet tall and wide. Leaves are maroon bronze with grey-green undersides and green central stripes. Foliage is somewhat twisting.

'Thumbelina'
1.5 feet tall and wide, with dark reddish brown leaves.

'Tiny Tiger' ('Aurea Nana')
A mini variety, barely topping out at a foot tall and wide. Leaves flush pink in cool weather.

'Tom Thumb'
2-3 feet tall and wide, with green, wavy-edged foliage that has red-bronze margins.

'Yellow Wave'
4-5 feet tall and 5-7 feet wide, with chartreuse leaves that have lime green edges.

Phormium tenax (New Zealand Flax, Harakeke, New Zealand Hemp)
This large, bold plant has bronze-green leaves and reach 9 feet tall and wide. New Zealand Flax grows well in USDA hardiness zones 8-11. Choice cultivars of this species are listed below.

'Atropurpureum'
('Bronze', 'Rubrum', Purpureum Group)
Plants in this group with purple or brown-red foliage that reach about 6-8 feet tall and wide.

'Atropurpureum Compactum'
('Monrovia Red')
5 feet tall with burgundy-bronze foliage.

'Chocolate'
('Chocolate Dream')
4-5 feet tall and wide, with with rich brown leaves.

'Radiance'
5-6 feet tall and 7 feet wide. Leaves are green and have central yellow stripes and green margins with a thin orange edge.

'Variegatum'
6-8 feet tall and wide, with grey-green leaves with creamy yellow stripes on the edges.

'Wings of Gold'
2-3 feet tall with grey-green leaves that have cream-yellow margins. Great for container plantings.

Caring for Phormium

Grow Phormium, or New Zealand Flax, in full sun to partial shade (between 4 and 8 hours each day). Ideally, these plants grow best when they receive between 6 and 8 hours of sun each day, but appreciate some shade in the late afternoon. Cultivars with dark foliage need a good amount of direct sun each day to attain their deepest color, and those with lighter foliage prefer morning sun. They require soil that is well-draining and moderately fertile with a pH of between 6.0 and 7.5 (slightly acidic to slightly alkaline). If local soils are particularly poor in nutrients or do not drain well, make sure to amend the planting area with plenty of organic compost before installing. Water newly planted Phormium regularly to help them develop strong root systems (about once a week). At maturity, these plants are considered drought-tolerant, able to get by on rainwater alone for much of the year with supplemental deep waterings during extended periods of drought. Colorful, variegated hybrids require more moisture, and should be watered whenever the top inch of soil feels dry to the touch.

Fertilize yearly in early springtime with a application of 2 inches of compost around the base of plants. Pull mulch back before applying, work the compost gently into the soil a bit, water it in, and then replace mulch. These plants are not heavy feeders, and this should be sufficient to provide the necessary nutrients for the active growing and flowering seasons. If grown in a cramped space like a tight border or container, they will need to be divided every few years to maintain health and prevent overcrowding. For information on how to divide Phormium plants, see the Propagation section below. New Zealand Flax can survive for decades in the garden before needing to be replaced. Clumps will continue to expand over time, providing new plants that can be divided and planted elsewhere, providing plants for the garden indefinitely.

Caring for Phormium in Containers
Phormium are wonderful in the ground, but can also be grown in containers. Choose a container that is at least a few inches wider and deeper than the nursery pot or root ball. Ensure that the pot has adequate drainage holes on the bottom to allow for excess water to flow away. Fill with a well-draining potting mix amended with organic material and perlite, and top with a layer of mulch to suppress weed growth, maintain consistent soil temperatures, and to increase soil moisture retention. Water regularly as the plant establishes itself in its new home. Once established, waterings can be lessened. Phormium plants grown in containers will need more frequent irrigation than those grown in the ground. As a general rule of thumb, water whenever the top few inches of soil feels dry to the touch. Prune to remove dead, damaged, or diseased foliage at any time during the growing season. Every few years, check the bottom of the pot to ensure that the plant is not outgrowing its root space. If roots are growing through the drainage holes in the bottom of the container, it is a good indication that it needs to be potted up; choose a slightly larger container and repot.

Propagation

Phormium plants are best propagated via division. These plants will also re-seed freely in the landscape, providing seedlings that can be dug up and transplanted elsewhere. To propagate your New Zealand Flax by division of existing plants, follow the instructions below:

Propagating Phormium by Division
To propagate via division, you will need a clean shovel, clean pruning saw (optional), extra pots if you are not going to immediately plant your divisions in the ground, and well-draining soil to fill the pots. To propagate your New Zealand Flax by division, follow the instructions below:

In fall, identify the area of plants you're going to divide. Start by loosening the soil around the plant with your shovel, working your way inward to avoid causing damage to the bulbs. Once you've gotten your clump out of the ground, run water over it or simply shake it to remove excess dirt. Then, lay it out on its side.
Separate the clump into multiple pieces, each with a healthy root system and adequate above-ground growth.
Prepare the planting area, whether it is a container or bed in the garden, and then plant the divisions. Afterwards, resume regular care.

Problems and Pests

Certain Phormium species are considered invasive in some regions; see the species descriptions above for more information. Check with local authorities before planting. Phormium plants are considered resilient in the landscape, but can suffer from issues with the following pests and diseases from time to time: