New Zealand & Mountain Flax
by Sonoma County Master Gardener Barbara Kirbach
If you’re looking for a plant to add year-round drama to your lawn, mixed border, decorative pots, poolside or even your parking strip, add a Phormium to your nursery cart. This evergreen perennial comes in all sizes and its leaves, whether solid or variegated, encompass a full spectrum of colors. Depending on variety, it can thrive in either sun or shade, is tolerant of our coastal sprays and winter frosts and is moderate in its thirst for water.
The genus has only two species, both of which are quite large: Phormium tenax and Phormium cookianum (or colensoi). However, it has wide range of more moderately sized hybrids with distinctive leaf colors that are crosses between the two species. The plant is a native of New Zealand, where it is widely grown for its valuable fiber; hence the name, Phormium, which is Greek for basket.
Phormium cookianum or colensoi, aka “Mountain Flax,” displays
Sonoma County Master Gardener Lyn Gannon, who has grown six to eight varieties of Phormiums over the past 15 years in Sebastopol, offers the following tips:
- Mature Phormiums can be half again as large as their nursery tags state. Do not plant too closely and surround with low ground cover to enhance their shape.
- Plant on a slight mound for good drainage. Do not bury the crown, plant too deeply or mulch too closely. This can cause crown rot.
- Plants are generally deer resistant, but gophers love them. Hummingbirds love the flowers, which are not very ornamental.
- Phormium hybrids’ variegated leaves may change to a dull green or brown in color or revert back to their parent foliage. Cut off the entire fan down to base of the clump. Remove flower stalks when blossoms wither.
- Mealy bugs are their most common pest. Check for them between the leaves of the plant. Remove by hand or use a horticultural oil.
- As noted above, P. cookianum and many of its varieties need some shade, especially from afternoon sun. Pink and cream leaves are especially susceptible to sunburn.
One of Lyn’s favorite hybrids is ‘Dazzler’ which grows 3 ft. tall and 5-6 ft wide with 1 ½ inch wide pink leaves striped in scarlet. The plant has multiple crowns, which can be divided in the fall or early spring -- ideally before a good rain. She also shares my fondness for ‘Jack Sprat’. True to the nursery rhyme, it remains a proportionate 12 x 12 in. dwarf with spiky bronze foliage in my 18 in. pot. ‘Thumbelina’ is another well-behaved dwarf. By contrast, my Phormium cookianum ‘Tricolor’ has shot up to 4-ft. tall by 6 ft. wide and has quickly outgrown its container. To echo Lyn’s advice, don’t be fooled by that four-incher in the nursery—unless it is truly one of the dwarf varieties!
Master Gardener Sara Malone has punctuated the gentle slopes of her garden with some 50 Phormiums. One of her favorites is ‘Dusky Chief’, which grows to a manageable 4-5 ft. tall with 1 ½ in. wide maroon-red foliage that turns bronze as it ages. Best of all, it can tolerate the Petaluma hillside’s full sun and dry conditions. She also favors ‘Golden Ray’ which has metallic-yellow striped leaves and thrives in full sun and wind.
Debbie Thomas at Sonoma Mission Gardens recommends the hybrids ‘Sundowner’, ‘Maori Chief’ and ‘Maori Queen.’ She describes the beauty of these Phormiums at sunset as “breathtaking,” as the last of the sun’s rays filter through the arching leaves and capture the brilliance of their pinks, reds, greens and bronzes.
Besides the nurseries mentioned above, you can find a good selection of Phormiumsat Emerisa Gardens, Harmony Farms, Urban Tree Farm, Mostly Natives and Wedekinds Garden Center. For a complete guide to countless varieties, visit San Marcos Growers’ website, www.smgrowers.com.