Gardening: When iris eyes are smiling

The Algerian iris is so exquisite that it deserves to be looked at closely.

FAMILIARITY MAY not always breed contempt, but it often breeds carelessness. Some of the very best flowers for my garden are under my nose (or sometimes under the noses of my friends and neighbours), yet I cannot see for looking.

When I think how beautiful are the flowers of the "Algerian iris", Iris unguicularis, and how accommodating it is once established, I feel ashamed that I have it growing in only one place in the garden, and scarcely give it a thought from one end of the year to the other. Until it comes into flower, that is, and then, for a brief moment, I recognise how lucky I am.

This carelessness has nothing to do with the off-putting name. In any event, for most of my formative years, this "beardless" iris was known as Iris stylosa, a name both memorable and perfectly easy to say. (Stylosa refers to the fact that the "style" is united for an inch above the flower base before it breaks into three parts, which is unusual, whereas unguiculus means "nail" or "claw" and refers to the narrowness of the bases of the flower segments.) I think it is because the Algerian iris is one of those plants that require no song and dance from the gardener, no exhaustive and exhausting feeding or pruning regime, in fact nothing special at all. It comes from countries which bound the Mediterranean, so it is used to hot dry summers and cool, wetter winters (which is why it flowers when it does) and emphatically does not need a rich soil. Provided you can find, or make, an area of infertile, very gritty, preferably limy soil in a south-facing border, say, against the house wall, you have solved its cultivation problems more or less permanently. If it doesn't flower well one year, it is much more likely to be because the summer before was sunless than because the clump is overcrowded.

So what is it like, this paragon of beauty thriving on neglect? It has flowers, 5-8cm across when fully open, held on the end of long, 15cm, smooth stalks. Inside, the three "falls" (the petals that curve over) are hairless, light purple, but with the most delicate mauve feathering on a yellow background near the base; these lines might have been painted on by a Japanese flower artist of infinite skill. The three "standards" are also light purple while the three-part "style" is mauve. The exterior of the petals, however, has the ivory pallor of a consumptive, and is thin enough for a hint of the feathering to show through. You see all that properly only when the flower is in bud and tightly furled like an umbrella.

If you pick the stalk of an unopened flower close to ground level and bring the bud inside, the flower will open quickly in the warmth and reward you with a sweet scent that will last for a couple of days. This is the best way of examining the flower, or for painting it.

Flowers begin to unfurl in the clump that I have in the last days of December, and though each only lasts a few days, there is a succession of them well into February. The exact flowering time depends where in the geographical range the ancestors of your plant were found. It may be as early as the autumn, or as late as February. The closely related species Iris lazica doesn't flower till March, and has shorter, broader foliage.

As well as one or two rare forms of Iris unguicularis, available only in a few specialist nurseries, there are three named selections that are widely sold. The first, `Mary Barnard', is even more beautiful than the type because the colour is a deeper, more luxuriant purple. Paler and, to my mind, a little wishy-washy, is `Walter Butt', and there is a white-flowered form, `Alba'. There is also a dwarf sub-species called cretensis. The best time to replant the rhizomes is in September, as soon as the autumn rains have started; these should be put into the soil a little deeper than you would the rhizomes of "bearded" irises, and in as large pieces as you can beg. If you are lucky, they will flower sparsely their first winter.