No accounting for some contrary plants

Press, 10 December 1982, Page 12

No accounting for some contrary plants

Country Diary

Derrick Rooney

Sometimes there are pleasant ways of discovering that one’s friends are not infallible. For example — a heat-loving South American member of ( the iris family is in bud in my garden now, in spite of the gloomy prediction of a friend that it would not flower south of Blenheim.

It is Neomarica coerulea, a fleshy-rooted perennial, not quite a bulb. You hardly ever see it nowadays, though it was once a favourite with many gardeners. Like nearly all other Southern Hemisphere members of the iris family, it has deeply pleated, sword-shaped leaves which would be a striking addition

to the garden, even if the plant never flowered. The flower stems are flattened, and at the top are curiously shaped buds which look like little birds diving towards the ground. As soon as the summer temperature reaches its mean maximum, these will start opening into blue “Butterfly” flowers, mixing sky blue and deep lavender blue with spiralling eye patterns of yellow and bronze. Each flower lasts only one day, but waves of them appear over many weeks. Propagation of this fascinating plant is by division, which must be done in late spring, when growth is beginning. Like all monocotyledons (grasses, lilies, bulbs generally) it must make new roots every year, and if transplanted in the dormant season it is likely to rot before it has a chance to grow. My plant had only a few minute white roots when it was sent to me in early September, and for a long time I thought that the friend who supplied it — knowledgeable though he be about bulbs — had jumped the gun. But in early October it suddenly perked up and by the middle of the month the roots which had been barely a centimetre long a fortnight earlier were coming out of the bottom of the pot. At that stage I planted it. How it will fare in the first severe winter I don’t know. In a Christchurch garden, where it is hardy in nine winters out of 10, established clumps usually come through the tenth winter, too, albiet battered. But that is a well sheltered garden. In my frost pocket it will be touch and go — neomarica is hardy to about nine degrees of frost, but we can get 10 or more. The young plant has not been fazed by this summer’s late frosts of as much as six degrees (we had two more of three degrees and one of one degree last week) but this is not surprising. Southern Hemisphere plants are, on the whole, much more, tolerant of unseasonal growing weather than are Northerners. A meteorology-minded friend tells me that this is because unseasonal frosts are much more common in the Southern Hemisphere than in the Northern, and have something to do with the distribution of land masses and the vast distances of sea between the southern continents. Be that as it may, I have noticed that Southern Hemisphere plants, from altitudes of 500 metres or higher, will survive severe frosts during their growing season. Lowland plants, however, may drop like flies. . ' This October,.for example, my native alpines were never looking better, while my variegated lemonwood, unharmed in four or five winters, was reduced to a pulpy heap.

Neomarica is one of a number of closely related South American genera which are grown in our gardens from time to time but, as far as New Zealand gar-

deners are concerned, are not at all well documented. The group includes the spectacular autumn-flowering tigridias (‘‘Jockey caps”), and the summer-flowering herbertias, alophias, and cypellas. Cypella plumbea, or should I say a plant under that name which I raised from seed a few years ago, is a free-flowering member of this group with an extraordinary ephemeral beauty. The flowers open in the afternoon. Curiously, they need plenty of sun to make them open, but wilt after only a short exposure to hot sunlight. When we have a cool, cloudy afternoon after a hot morning, they last until the next day. The specific name of this plant, plumbea, comes from the Latin word for lead, and is descriptive of the flower colour, which is noted in several reference books as a leaden grey-blue. My bulb has light blue flowers with contrasting darker and paler markings in the yellow eye. The foliage is light green and deeply pleated, and the bulbs are bright orange. I’m not at all sure I have the right name for it, because while the’ flower colour can be explained by natural variation, the orange bulbs cannot. The coloured bulbs are so distinctive that they surely must be considered a signifi- ' cant point of identification, but even Brian Matthews, of Kew Gardens, makes no mention of them in his two excellent books on bulbs. That’s the trouble with South American plants — unless you can read Portuguese •or Spanish you can never be sure what you've got. v My cypella could easily be made to- fit in herbertia or neomarica as we know them.

Herbertia platensis, which I used to grow, also has light blue flowers, and a bright orange bulb which is often

mentioned as one of its key features. But this is a much bigger plant than my cypella, having large, deeply pleated leaves which may grow a metre high, and it is deciduous, resting in the winter, whereas my cypella is evergreen. Of course, I could have an evergreen form of herbertia. It’s not unusual to get the plants in this group under several different names; the prime example is the species often listed as Alophia pulchella in seed lists and catalogues. Sometimes it appears as Herbertia pulchella. It has flowered for me under both names, and is indistinguishable from a bulb that a friend and I both raised from seed as Alophia lahoe. The latest information (from Kew Gardens) is that the correct name for this plant is Trifurcia lahue. You pays your money, and you takes your choice! Most of the better known plants in this family have blue flowers, and most of them are fairly hardy - though they do not like to be very wet in winter, while they are dormant. I had

Herbertia platensis doing very well for several years, but’after the very wet winter of 1978 it failed to reappear, and where its bulb had been I found a husk filled with slimy, foul-smelling muck. It had rotted. All its seedlings that . I had been rearing disappeared, too, and I am now without it. I have found the tigridias. especially the lovely apricot one which is hardly ever offered by nurseries, much more tolerant of adverse winters. Books on bulbs generally advise gardeners to lift their tigridias in autumn and store them in dry sand over winter. But I leave my bulbs out in the garden all year, and though the soil in which they are growing is often frozen solid for weeks on end in winter, they have, so far, always come up again. Tigridias are the odd men out in this family in that there is not, as far as I know, a species with blue flowers. They come in shades of red, yellow, apricot, peach, and a very vigorous white, and flower in late summer and autumn. In mild gardens seed sown in spring will flower in the autumn, but for me the bulbs take two years to reach flowering size. They need plenty of water in summer. A handsome yellow in this group which I admired a few years ago in a Cashmere garden is Cypella herbertii. I raised a batch of this species from seed and planted it out last year, but now I cannot remember where I put it, and I fear it has been lost in the bun rush for light (some parts of my garden are very crowded). If it’s not dead I will stumble across it in flower one day and get a pleasant surprise. If it is dead, well, you can’t miss what you’ve never had. New Zealand is one of the few Southern Hemisphere countries in which this family is poorly represented — the only members of the iris family in our native plants are four species of libertia. There are no “true” irises in the Southern Hemisphere. but the family, Iridaceae, is a significant component in the floras of South Africa, temperate South America, and Australia.

Best known among the South African representa- ■ tives are the many species of. gladiolus, some of which* have been hybridised in, the Northern Hemisphere ■ to create a race of large-flowered garden plants. « Running a close second are* the moraeas, or "butterfly.' irises.” Moraea spathulata, atall plant with deep yellow flowers, is the hardiest of these, and one of the best..' Also worth looking for aie; Moraea bicolor (now separ-1 ated into its own genus, as' Dietes bicolorj, and M. vil-.-losa. The first two are ever-; green and not difficult to grow, though they resent’ division — my Moraea, spathulata has not flowered,; in fact it’s hardly grown,since I divided it three years; ago. Moraea villosa is trickier,; I suspect because it is highly vulnerable to moisture during its long dormant period.! Whereas the other two are evergreen, M. villosa does not emerge from the ground until late spring, and it disappears soon after flowering in early summer. The flat flowers are about the size of a 50c piece, and are white, with a bright blue band round the eye. There was one on my rock garden the other day. It is one of the prettiest of bulbs, but has its . little tantrums. It comes and - goes; some years you see it, ‘ some you don’t. In my garden it doesn't flower after a wet summer, : and sometimes, if conditions ■ are not to its liking, it skips a season altogether. I don't think it dies — it just throws a sulk.