June 6, 2014 5:19 pm

Bearded beauties: the best irises to grow in the UK

French and English growers share their expertise on which varieties are best suited to gardens north of the Channel
Iris Marron Chaud©cayeux-irises.com

Iris Marron Chaud

Despite the recent wet weather, I am having an excellent iris season. Some of them hate my soil and refuse to flower. Others are naturally shy. The best, however, are so showy and so amazing in their colours. As you can guess, I am not growing the tasteful brigade’s favourite, the sky blue Jane Phillips, wonderfully free-flowering though she is.

I have just engaged in some intimate research with two great growers of irises, one French, one English. My question was simple. For Financial Times readers, which are the best tall bearded varieties (the ones which flower in Britain from mid-May until mid-June)? We are all lost in the ocean of modern hybrids, the ones that win prizes at trials from Paris to Florence. What should we choose if we are not exhibitors but want to be up with fashion?

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Robin Lane Fox

I will begin with the French. To transform your ideas of the range and brilliance of modern irises, go to the website of Cayeux irises (iris-cayeux.com). The online catalogue is a revelation, with pictures of about 650 different varieties, 170 of which have been bred by the Cayeux family themselves. Will they really flower in Britain and which are especially good?

I have just had a personal tutorial from Richard Cayeux, a grower with 31 years of experience and a record of medals for exhibits at Chelsea. I have admired them, of course, but I have been a Francosceptic. Will irises from a nursery southeast of Orleans really flourish and flower in colder parts of Britain? How can we choose the best from a list of so many, grouped in such tantalising collections that we want to buy them all? Ignorantly, I asked Cayeux how long his nursery has been breeding new varieties. The answer is a span of four generations, past grand-père to arriere-grand-père where my French starts to fail. Kindly, he agreed to name his top varieties for gardeners in Britain. They differ somewhat from the nursery catalogue’s lists of tops, favourites and so forth. Here are his choices: Planeur, Ravissant, Marron Chaud and Tel Arlequin. I had hoped he might name the one called Megabucks specially for FT readers, but it did not even make the top 10.

Iris Tel Arlequin©cayeux-irises.com

Iris Tel Arlequin

The point about these four, he says, is that they will flower extremely freely, even without any French soleil ardent. Before I discuss their colouring, here are some important details. Irises are best planted in the weeks from early July to early October. In Britain, I believe, the earlier the better. Never feed them with high nitrogen fertilisers like Miracle Gro and so forth, which encourage lush growth and will rot and ruin the root-like rhizome. Instead, I put bonemeal around them twice a year, once after flowering and once in early spring. It seems to work very well. In France the advice is to divide the plants every four or five years, cutting out the older rhizome roots in the centre of each clump and throwing them away. Only the young outer rhizomes should be replanted. The British fashion is no longer to cut the fans of leaves by about two-thirds when they are replanted. Cayeux cuts them nonetheless, with typical French neatness.

Iris Carnaby©Tim Gainey/Gap Gardens

Iris Carnaby

As the flowering season is ending, the huge iris fields on the Cayeux nursery have closed this weekend. Next year, you should plan to add them to your French travels. They are at their best from about May 5 until June 1, and the pictures show that their best is truly wonderful. Obviously, the seasons vary, but Cayeux has a freephone line for UK callers (0800 096 4811) and another for non-UK English speakers (0033 238 670 508). They are kept updated with the season’s progress and timing. Meanwhile, the ordering season is still open, although orders are dispatched in sequence of receipt. Up to £150 in value, an order from Cayeux costs about £9.50 to deliver to Britain. Prices vary with the exchange rate, but they are no longer a deterrent, as our homegrown nurseries charge £6.50 or more for an iris rhizome. The latest prize winners at Cayeux cost up to £11.50, but others come in at £4.40 or less. My prejudice that they must be “prohibitive” for gardeners abroad is completely wrong.

Now for details of Cayeux’s top four. Marron Chaud is a self-explanatory hot shade of chestnut brown. Planeur has white “standards”, which are the top petals of the iris flower which are held upwards. Its “falls”, or lower petals, are a deep blue, born almost horizontally. Ravissant is next, but it would not be my first choice from its photo alone as its standards are lilac white and its falls are white too. The point is that it flowers exceptionally well and can be forgiven its rather pale colour blend. I had already noted down the fourth choice, Tel Arlequin, on this year’s Chelsea stand. It has yellow standards and plum-violet falls, the sort of colour combination that is only found in irises. It can carry as many as eight buds per stem as they branch from low down on its length. It looks superb.

Iris Actress©Michael Howes/Gap Gardens

Iris Actress

Maybe you prefer to stick with the expert’s own nominations. Under pressure he added a fifth, Eclipse de Mai, a marvellously rich dark violet whose falls are even darker, like an eclipsed sky. Nonetheless, I have two choices of my own to add from Cayeux’s list because they are varieties I already grow well. One is the amazing Mer du Sud whose flowers are a rich deep blue. It has flowered with me as freely as promised and I see why it won the RHS’s Award of Garden Merit after trials here in the UK. So did my other winner, Alizes, whose colours are less dramatic, combining pure white standards with white falls that have a mid-blue border. I can only say that it stands out at a distance in my garden and is exceptionally free with its flowers. Both these superb irises were bred in 1987, perhaps a reason why they did not come into their nurseryman’s top picks.

Now for England’s answer. Since 1851, Kelways has been a name famous for iris growing. At Langport in Somerset the name survives in an excellent plant centre that has surmounted the ups and downs of past business (kelways.co.uk). At this year’s Chelsea I was treated to the exhibitors’ top three selections. They are more widely known than that of Cayeux, because they are not new to Britain. Iris Beverly Sills is a lovely pale blend of pinkish white. Actress is a superb ethereal pale blue, which is recommended for holding itself so long in bud. Carnaby is a bicolour with pink-purple falls and another superb flowerer.

Which shortlist is the one to choose? Myself, I will choose both, expecting both to perform superbly, just as their nominators believe. You may prefer to judge from their pictures on the online catalogues, but remember my request was for irises that will flower in all weathers. It is easy to be seduced by others which oblige only in hotter years. One rhizome of each variety soon spreads into many more and allows you to build up a big group. As usual, you get what you pay for. Those ancient yellow irises may be your pride and joy but once you have seen what experts have bred, you too will want to be up with the best of the game.

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