PHORMIUM. New Zealand flax. New Zealand (where else would you expect?). Two species of evergreen perennials in the lily family. Most earlier selections, while attractive, are too overpoweringly large and bold for a permanent site in the average garden. Beginning in the late ’70s and ’80s, however, Duncan & Davies and other New Zealand nurseries made available a colorful line of dwarf and intermediate selections, useful in a variety of garden settings. All have the compact, clumping habit and fans of narrow, folded leaves typical of this group. I have learned to be skeptical, however, about any claims for their ultimate size. Three feet in the official descriptcation may well translate into 5-6’ in the garden of reality.
There is another problem which has not been sufficiently well publicized: Some of the showiest selections have variegated color patterns in the leaves, and in many cases these are unstable. Reverting green or bronze shoots tend to outgrow those of the desired pattern and can overwhelm the plant if not quickly removed. Needless to say, this can be a disaster in large commercial landscapes, where aftercare tends to be minimal.
Flowering shoots, which form only on older plants, will rise above the foliage carrying clusters of interesting brownish red to yellow tubular flowers. It is as well to remove them, to promote continual production of the more ornamental leaves. Sun or light shade, most soils, moderate to occasional watering. Hardy to around 15oF.
colensoi (cookianum). This is the smaller-growing of the two species, which means that the typical form reaches “only” seven to eight feet. From it are derived some of the best of the truly dwarf phormiums. The leaves are usually gracefully arched, making nice fountains, and softly shiny in surface. The flowering stems are only a little higher than the leaves. It is hard to know exactly which of the recent cultivars belong here; several selections listed under P. tenax by Duncan & Davies are assigned to P. colensoi in the new RHS Dictionary of Gardening.
‘Chocolate’. While another bronze phormium would seem to be just what the world doesn’t need, this one is not bad. It has broad, shiny, widely spreading leaves. These are deep green with a heavy overlay of bronze.
‘Chocolate Baby’. This is a true dwarf, growing 2-3’ high. It makes dense clumps with narrow, arching, solidly dark, slightly reddish brown leaves. Their surface is strikingly shiny.
‘Cream Delight’. A recent and already very popular introduction. It reputedly grows to 3’ or less, and has spreading, gracefully arching leaves. These show a broad, cream-yellow central band and clean dark green margins, plus some narrower, darker lines. The contrast is quite striking. It has been quite stable to date.
‘Duet’. An even more recent arrival, destined to become a popular garden plant. It makes clumps as dense as those of ‘Cream Delight’, with straighter and slightly narrower leaves, and stands more erect. The leaf colors are very similar, but reversed, so that a dark green margin surrounds a pale yellow center. It has been stable to date.
‘Dwarf’. Not a very imaginative name, but the plant is nice enough. It is a plain green phormium with relatively broad, shiny leaves, spreading rather than upright. It is alleged to stay below 3’ in height.
‘Platt’s Black’. This is one of several recent selections that are “beyond bronze”. It makes profuse fountains, allegedly only 2-3’ high. The leaves are narrow, unusually shiny in surface and exceptionally dark, combining intense reddish brown on the upper surfaces with an odd greyish bronze on the lower for a glittering effect.
‘Tricolour’. This selection arches to 3’ or a little more. The leaves are heavily and irregularly striped with cream on a dark green background. There is a fine red pinstripe around each margin, most noticeable in the winter months. In the twenty-odd years I have grown it, I have yet to see a reverting shoot (perhaps I should be more careful about tempting Fate).
tenax. The better-known species, and normally the larger and bulkier. The following selections all depart from this tradition, however.
‘Amazing Red’. One of the smaller cultivars, growing about 3’ high. It makes particularly dense clumps, with rather narrow, dark reddish brown leaves. The color is particularly intense during the cool season (is this the “amazing” part?).
‘Apricot Queen’. Another profusely clumping dwarf (about 3’). The leaves are mostly gold with an apricot overlay and broadly margined in green. A hairline of maroon is evident along the margins in cooler weather.
‘Bronze Baby’. Certainly not a baby, but a relatively small (perhaps 3-5’) phormium with arching, highly polished leaves. It is one of the most intensely colored of the “bronze” phormiums, only a little less red in tone than ‘Amazing Red’, above.
‘Dark Delight’. (P. colensoi in RHS). This is the latest sensation among phormium lovers. It is less rampant than most, slowly increasing from a narrow base. The leaves are up to 3’ (or more??) long and colored a uniform, vivid reddish purple.
‘Dazzler’. The name is no exaggeration. The leaves are long but narrow and arching. They are painted deep maroon with brilliant red striping. Reverting shoots began to appear recently after many “stable” years. Fortunately, the reversions are nearly as showy as the desired pattern, somewhat resembling ‘Dark Delight’, above.
‘Dusky Chief’. This is one of the more unusual “bronze” cultivars, with rather stiff, narrow leaves held nearly erect. Their color is a deep brownish purple on the upper surface; on the lower they have an almost chalky greyish overlay.
‘Guardsman’. This is hands-down the most striking of the newer phormiums. It is alleged to grow 5’ high, but I expect it to be taller still. The leaf-fans are narrow, the leaves quite straight and rigid. The central bands of the leaves are deep green with a strong red overlay. The edges are deep coral pink even in summer, when most phormiums fade, deepening to a vivid red in winter.
‘Jack Spratt’. One of the first small cultivars introduced in California, still popular in spite of the wealth of new choices. It grows about 2’ high and has narrow, slightly twisted leaves. These are bronze overall, somewhat redder at the margins.
‘Maori Chief’. A robust selection, growing to 5’ or more. The leaves are broad and thick-textured. Their color pattern includes a broad central swath of bronze-green and a rosy margin, paler in summer and vivid in winter. It has been the only stable member of the Maori series here.
‘Pink Stripe’. A prolific plant with broad, barely arching leaves, usually growing 3-5’ high. The leaves have wide bronze-over-green central bands and narrow pink marginal stripes, most impressive in winter. The margins narrow and fade on older leaves.
‘Rainbow Warrior’ is a reselection I made from a group of the ‘Rainbow Hybrids’ seed strain. The leaves have centers of deep, glowing pink, turning nearly blood red in winter, with narrow dark green margins and scattered green lines. It becomes unstable at times, then stable again. At its worst, it has been better-behaved than most of the Maori series.
‘Sundowner’ (P. colensoi in RHS) is nearly the reverse of the preceding selection in color scheme, though the margins are considerably broader. In this case the bright pink is on the margins, while the green forms a broad but variable central band. A Duncan & Davies selection, it has been one of the most stable cultivars of this color scheme to date.
‘Surfer’. This was once touted as a 1’ miniature but is already twice that height in nursery containers. However, it is still well within the “dwarf” category. It makes dense clumps. The leaves are narrow and somewhat twisted, dark green in background color with a bronze overlay.
‘Variegata’. One of the first of the colored-leaved phormiums. It grows at least 5’ high and has rather stiff, straight leaves. They have a medium green background and light yellow margins with some green striping.
‘Yellow Wave’. 3-5’ high, with broad, shiny leaves. These have bright yellow centers and green margins.