The winter stress test

Image of Robin Lane Fox

Just when the British weather warms, frosts and cold greyness return to hold us all up again. How are winter flowers reacting to it all? I would expect them to have given up. One reason why I value them so much is that I am largely wrong.

Winter Sweet seems totally untroubled by the recent stress tests. Its scent is unsurpassed, sharper than the Chanel No 5 into which Coco Chanel is said to have mixed an unprecedented number of ingredients. Winter Sweet, or Chimonanthus praecox, was not one of them, although it almost anticipated her result.

I have not seen a better crop of flower on old bushes in Oxford, not least because their petals seem so frost-resistant. This shrub takes up to seven years to flower well, at least in the praecox luteus form which is most widely on sale. Do not let this fact deter you. The shrub that you buy will be two or three years old already and the remaining time soon passes. I continue to wonder what ever is the pollinating insect in its native China that is drawn to its exceptional scent.

Against walls the outlook is more mixed. Some of the taller climbers are the plants that have suffered most and the reason must be their lack of a protective snow blanket when the wind is most icy. Snow does not stick to a self-clinging wall-plant. As a result I look out on the worst damage for more than 20 years to the “evergreen” variety of Climbing Hydrangea, Hydrangea seemannii. Its leaves, facing east, have all turned brown and I am counting on some regeneration in warmer weather. The omens look quite good, so I will do nothing, wisely.

They look less good on a less hardy climber, the lovely white-flowered Solanum jasminoides album. This one has become hugely popular in warm London but even there I notice that its top-growth, as on mine, is brown and dead. Here, above all, the remedy is to do nothing in a hurry. At worst, this Solanum may regenerate from just below ground level in late spring, whereupon the top growth will have to be cut off and thrown away. At best, some of the brown tangle will resprout too, so do not attack it too quickly in the first bout of spring cleaning.

The good news is the return to flower of the amazing Winter Jasmine, Jasminum nudiflorum. If this plant was new or rare we would all be stampeding to grow it. It has those lovely yellow flowers and is entirely hardy, though best when left to fall forwards at the base of a wall. It also makes an unusually good cover for slopes and banks. It has the most winter-proof constitution. It was flowering spectacularly in late November, just in time for the hard weather to ruin all its flowers. Now, it has started all over again from a second crop of buds. What summer-flowering plant would be so generous?

Its stamina is matched by others. The superb Winter-flowering Cherry, Prunus subhirtella autumnalis, simply grows on beyond the point where the early frost interrupts its first flowers and then sets new buds, now starting to open. Generously, the winter-flowered Viburnums do the same. Mine were just coming out in November, the start of their season, when the snow browned every flower in sight. They have set more buds and started again, prompting me to track the history of the underlying wild parent.

They turn out to be spectacular in Kansu and on the lower foothills of the Da Tung mountains, out on the borders of China and Tibet. Botanical innocents think there are two separate forms, Viburnum farreri and Viburnum “fragrans”, so I have been buried in the memoirs of the great plant-hunter Reginald Farrer who was active in the area in 1914. He recalls the pink form of Viburnum “fragrans” in most of the local gardens.

I have not yet found him discovering a separate “farreri” which was to be named after him. In fact, botanists now collapse the old Viburnum “fragrans” into farreri anyway, with the result that he has given his name to far more plants than he ever expected.

For him the finest form was pink. When he saw it in full flower for the first time, he described it as “an epoch-making instant in everyone’s life”. Nowadays we grow more of the hybrid Viburnum x bodnantense, of which Dawn has the pinkest flowers, so you may be deceived by its epoch-making impact this weekend. Plain farreri waited until April to flower in Kansu and in a typical flurry Farrer then fell for its “pink-lilac spikelets, breathing an intense scent of heliotrope”. Mine has added plenty of pepper to that heliotrope and its flowers are only white. A special Farrers Pink has now been disentangled and is offered by four British nurseries in the new RHS Plantfinder for 2010-2011. In his honour I will buy one.

My white one, however, has pleasant roots in his memoirs too. In 1914, in the little town of Sining, he passed the time by dining with the local governor. His host was a real Manchu with some of the civilised Chinese taste of the time. His garden was full of lilacs, potentillas, peonies, viburnums, roses and jasmine. He even had a heated greenhouse in which he forced potted bushes of white viburnums, the ones we now know as farreri. His dining table was set with them in February, so Farrer sat down to dinner among pots full of forced viburnums as “sweet as the best white lilac”.

His host even gave him a white-flowered plant to take home. Is it, perhaps, the ancestor of our best white nowadays, Viburnum farreri candidissimum?

There was only one blot on an evening whose conversation was enhanced by small glasses of wine. The viburnums, Farrer observed, were displayed in “horrible European vases”. There are surely no more viburnums on tables for meals in towns on the Tibetan border. But there is none, either, on tables in advanced gardening countries like Britain. In memory of this dinner I suggest we bring them back.

Buy a young plant of Viburnum farreri, preferably the “candidissimum” form if you want the very whitest scented flowers. Pot it up and grow it on if you have a heated greenhouse or conservatory. It ought to flower from November onwards, a simpler alternative to scented gardenias.

I say “bring them back”, but I find, as so often, that the FT’s former gardening expert, Arthur Hellyer, was already alert to this trick. He lists potted deutzias, lilacs and viburnums as jobs that need attention in greenhouses in early February.

After the first forced flush, his advice is to bring in a few more potted plants of these shrubs and push them into flower indoors to “provide a succession to earlier batches”.

Where the governor of Kansu province was in 1914, FT readers were advised to be in 1960. In honour of these repeat-flowering winter shrubs we should resume the tradition next year.

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