This drought is not all bad news

Press, 13 February 1981, Page 10

This drought is not all bad news

GARDENER’S DIARY

Derrick Rooney

The most immediate effect of a drought such as the one we are now having is on the size of the crop — the yield — and this is becoming sickeningly apparent as spring-flowering bulbs are lifted for replanting. It was struck the other day, while lifting a few clumps of colchicums for re-establishment elsewhere in the garden, by their smallness; some corms which should be as big as a clenched fist were scarcely bigger than daffodil bulbs. Crocuses are suffering, too; last month- a bulb grower of many years experience apologised for his inability to supply my order of crocus species this year;, many of his bulbs were scarcely bigger than rice grains. My own experience, and that of several other enthusiasts with whom . I have discussed the problem, have been similar. Crocuses have not flou-' rished in many Canterbury gardens this season, and

some species apparently have diminished both in size and numbers. But the bad penny, does have a shiny side. There seems no reason, given an ordinarily wet winter and. spring, to fear for an absence of flowers next season. The autumn disp.ay, such as it will be, should be good, too. There may not be many flowers, but- they .will be good ones. All the colchicums . that I lifted last week, for example, were crammed with flower buds, in spite of their small size, and a few autumn-flowering crocus bulbs that I found after a poke about in the rock garden were small, but well studded with fat buds.

Some larger relatives of the crocuses —• Dutch irises — have small bulbs this year, too; where they should be as big as daffodil bulbs when well grown, this year’s crop is hardly half as big. But they are well rounded, firm, and should flower well next summer. The hot weather may have stunted growth, but it has also ensured that the bulbs are getting a good “baking” — the term used by enthusiasts to describe the ripening princess that bulbs must undergo in summer if they • are to flower well in the succeeding spring. Nearly all bulbs come from areas with clearly defined seasons, one of which is a long spell of almost total drought during their dormant season. Without such a dry period, bulbs are apt to cease growth too late and resume it too early; they become soft and prons to pests and diseases, and do not flower well. I like the bulbous irises, and now that I have, I hope, discovered the secret of growing them, I plan to have more in the future. They flower just. after the dwarf and intermediate bearded irises, ' and in my garden may eventually take the place of th.- “TBs” — the tall, bearded irses, which I am eliminating one by one because they do not have enough resistance to wind. There are a number of species of summer-flower-ing bulbous irises, all from Southern Europe, North Africa, and Asia Minor. Most of the bulbs in cultivation are not, however species, but hybrids between several Southern European species in the series Xiphium of the iris family. The most common, and most easily grown, are the Dutch irises, so called because thev were hybridised from the early years of this century by Dutch bulb growers, and ■

exported in large numbers. Iris xiphium itself, known in cultivation as the “Spanish iris,” grows about 2ft tall and has delightful flowers in a wide range of colours from white to blue. The Dutch growers increased the size of its flowers by selective breeding, and crossed in other species to give, a wider range of colours and an extended flowering season. Numerous named varieties are available. “Golden Harvest,” an old one, is still the. best yellow; “Princess , Irene” is another' good one, with white standards and or-ange-yellow falls. Among the blues the oldest of all, “Wedgwood,” is still unbeatable. It is an earlyflowering form of Iris xiphium crossed with the winter-flowering Algerian species, Iris tingitana, and it has inherited the precocious habit; it flowers some weeks before most of the Dutch irises, and always at a time when a splash of pale blue is welcome.

Iris tingitana itself is indispensible in garden?

where it will succeed, but as it comes from Tangiers and is used to continual warmth, throughout the year it does not thrive in . colder areas. In-my garden it grew for several years, and came through the winters with foliage unscathed by frosts, but flowered only once, after an unusually mild winter, and eventually I scrapped it. The leaves are hardy, but the flower buds, which form in the autumn, are destroyed by frosts heavier than 5 deg. “Wedgwood” is a highly acceptable and completely hardy substitute. : The cultivation of these bulbs is often described as “difficult,” but really, once their needs are understood, they .are easy to grow and flower year after year. Their chief enemies are virus disease and a pest known as eelworm; the former can be prevented by keeping a sharp eye for insects in spring, and giving the foliage a protective spray at regular intervals during mild weather; the latter by regular lifting, and

replanting every two or three years in fresh soil. They love superphosphate — as indeed do almost all irises — and appreciate a sprinkling of dolomite lime, too. But all the fertiliser and all the spraying in the world will not make these bulbs thrive unless they are planted at the right time.

Although they heed a period of complete dormancy in summer to complete their . ripening, the dormancy lasts only a short time —- a much shorter time than is the case with most bulbs. They need not be lifted more often than, every second year, unless the summer is abnormally wet, and when they are lifted they should not be left out of the ground much longer than three weeks. After that they start to shrivel.

Aftercare is an important part of lifting them. The bulbs, once dug up, should be left inside the remains of their old tunics until they are thoroughly dried off. This takes a week, and then, and not before, they should be cleaned.

Flowering-size bulbs may then be stored for a couple of weeks in a cool, airy, shady place — never in the sun — but the smaller bulbs and bulblets should go back into the ground immediately.

I am sure that one of the major reasons for failure with Dutch irises is that bulbs bought from shops and garden centres have very often been out of the ground far too long. Take a close look at the bulbs before you buy them. If there are new, white roots emerging from the bases, don’t buy them. Dutch irises — and all others of the Xiphium group — are so keen to get growing in autumn that they will if necessary draw on their internal reserves, and start into growth while still on the shelf.

Once this process starts, the bulbs deteriorate rapidly. Even refrigerating them seems to have little effect. You may be able to fool some of the gardeners all of the time, and all of the gardeners some of the time, but you can’t fool Dutch irises any of the time in autumn.