12 JUNE 2004, Page 62

Kanzan epidemic

Ursula Buchan

It is said that people often catch divorce from their friends, as if it were an infectious disease. It is certainly true that gardeners catch plants from their neighbours. Although this is hardly as harmful to all concerned, it can certainly be a disadvantage, at least to the impartial observer. Robinia `Frisia', Spiraea `Goldflame', and `Castlewellan' Leyland cypress all break out from time to time in a district, like a dose of yellow fever. Worst of all, in my opinion, however, is an epidemic of the double pink ornamental cherry, Prunus `Kanzan'.

At the end of April, my husband and I spent a sunny weekend on the north Norfolk coast. It was marvellous spring weather for walking on the edge of salt marshes looking at birds. Occasionally we would turn inland to take in a picturesque village (of which there are many) for the purposes of churchand pub-visiting — usually in that order. The village gardens were looking wonderful: lushly green, full of bright tulips and spring promise. But in far, far too many of them, especially those belonging to `done-up' houses, there was one of these wretched cherry trees. Indeed, in all my years of shivering convulsively at the sight of `Kanzan', I never remember a weekend of such continuous tremor.

Even if you do not know the name, I am sure you will recognise the description. `Kanzan' is the stiff-branched, vase-shaped cherry tree with copper-bronze young leaves appearing at the same time as extravagantly double, silly, frilly, purplishrose flowers. It has some orange autumnleaf colour, true, but nowhere like as good as Prunus sargentii, say. Because the flowers are double there are, of course, no cherries for the birds and the branches spread towards the horizontal only in the tree's later years.

`Kanzan' is one, indeed the most famous probably, of the Sato Zakura, the collective name for Japanese Garden Cherries, that race of revered trees bred over centuries in Japan, but whose origins are now mistily obscure. A few, such as `Tai-Haku' or `Shirotae (both white), are trees of great personality and charm. `Kanzan' has personality in spades, but its lumpy flowers are decidedly short on charm. Its offspring, 'Pink Perfection', is a better bet, having clearer pink flowers and less bronzey leaves.

W.J. Bean, whose pre-war Trees and Shrubs Hardy in the British Isles (four vols) is still widely consulted by thoughtful gardeners, damned Prunus `Kanzan' with generous praise in 1933. 'The most widely planted of the Sato Zakura,' he wrote, 'and understandably so, for it is of excellent constitution, very free-flowering and of the right habit for street-planting. Its only fault, apart from the impure pink of its flowers, is that in gardens it usurps the place of other cherries of more charm and character, and that it is too often planted in country districts, where it is grossly out of place in the spring landscape.' Too right, old Bean. In a countryside so full of natural, understated beauty as north Norfolk, what possesses people to overlay it with these stiff-necked trees and flowers the colour of cheap strawberry ice-cream?

Sure, `Kanzan' is of vigorous constitution but, as with most Japanese cherries, if planted in a lawn, as it so often is, the roots annoyingly run just under, or even over, the surface of the grass, making mowing a positive torture. It is also susceptible to bacterial canker, cherry leaf scorch and silver leaf, although in that regard it is no different from any other Prunus.

Why do Norfolk village gardeners catch the contagion of this tree from their neighbours? In countless cottage gardens, which until quite recently would have been graced by useful, homely 'Bramley' or 'Norfolk Beefing' apple trees, with their wonderful April pinkish-white blossom, this interloper pokes its gawky limbs above many a fine — and expensively renovated — brick and flint wall. Even if the 'Bramley' no longer seems suitable, why not a soberer ornamental crab apple (Malus), which is much less prone to disease than Prunus, or even a fruitful quince tree, such as `Meech's Prolific'? (My quince trees all came from that excellent Norfolk nursery, Read's of Loddon, the other side of Norwich — hardly too far a journey for the Ssangyong Musso 4x4, I should have thought.) The only mercy is that this prunus, like most other Japanese cherries, is not longlived. Forty years is a good span, 50 if you are unlucky. So those `Kanzan' cherries that were planted when north Norfolk was gentrified some 20 years ago are roughly halfway through their span. It is unwise to replant a cherry with another, so the question inevitably arises, what will these gardens go down with next?