Plants and the seasons; and the vexed question of when spring begins

Press, 30 August 1979, Page 12

Plants and the seasons; and the vexed question of when spring begins

GARDENER’S DIARY

By

Derrick Rooney

One of my favourite wet-winter’s-day pastimes is making lists of plants that are easily fooled by the weather. There are quite a few of them — plants that come, usually, from a harsher climate than ours, or from places where the seasons are more clearly defined, and which can be encouraged to break their dormancy by a mild spell at any time from May to September. The wild cherry plums (Prunus cerasifera) come near the top of the August list. Invariably, a mild spell early in the month encourages them to burst out into blossom, and almost as invariably a storm later removes most of the potential fruit. They have done it again

this year, and I should think that after, the rain of the last few days most of the pollen from the wild cherry plum at the bottom of our garden is half-way to the sea. Fortunately, the bird cherries (Prunus avium) that are making a thicket in our hedge and beneath our tall poplars (appropriately screening part of our chicken run) have more than bird, brains, because they restrain themselves until much later; there is not often much frost about when the bird cherries flower.

1 cannot say the same of the flowering apricots, which come into blossom sporadically from midwinter on, whenever a warm spell bewitches them.

These are hybrids or cultivars of two Eastern species, Prunus mume from Japan, and P. armeniaca from China, and in their native lands, I believe, they are springflowering only. The seasons .there are sharply defined, and once, dormancy begins it is strictly enforced.

The habit of making successive minor displays before the main effort here, is quite a pleasant one, really, because there is no fruit set to worry about, and if frost does blacken one or two waves of pink there are always plenty more to come. Our garden has two of these trees. One, which I planted, is the deep pink “Sangiiinea” (why is this not seen more often?), and the other is an old. nameless but potentially pretty cultivar of Prunus mume, unfortunately on its last legs — three-quarters of the wood is dead. It still carries a good scattering of flowers from mid-July on, and a heavy remedial pruning that it deceived this winter, when I got into it with a chainsaw, might help to revive it. A sprinkling of fertiliser in the long grass •around it later on might help, too.

Daffodils and bluebells and the pretty but insidiously invasive blue bellflower (Camp-

anu 1 a ranpunculoides) grow in this grass, and sometimes the early daffodils. like "Double Sion,” or the "Solei! d'Or” jonquils come out at the same time as the tree has its main flush. The effect is charming, and probably deserves a better background than a netting fence. But you cannot have everything. Smaller plants also display anomalies in their timing. Hybrid primroses with Primula juliae blood, for example, are easily fooled and are liable to burst into flower at any time of the year, even in midsummer if there is a cool, wet snap. But Primula juliae itself flowers in spring only, and "pure” P. acaulis primroses, though a few weeks earlier, likewise restrict themselves to spring. Sildanellas, the lovely relatives of primulas from the cool subalpine woodlands of Europe (they are

not hard to grow in the shade of a rock) flower in their homeland after the snow melts, but here, if slugs have not eaten out the crowns in autumn, they flower in late winter. Fortunately, their nodding, fringed blue flowers are not harmed by frost. Some plants are not easily fooled. I have a small rhododendron (I think it is R. hemitrichotum) which is often in flower during the August school holidays, while the children are at home. But sometimes it is late (it is this year), and the lateness seems to be independent of warm spells. The bush must have a built-in barometer, because once it is wreathed in its little pink and white flowers (all the way along the branches instead of at the tips only as in most rhododendrons) it seldom suffers the indignity of a storm. The display lasts only a week or so, but is quite enticing, becuase the golden-flowered Berberis stenophylla “Gracilis” is nearby, and underneath are early daffodils, crocuses, primroses and violets. All these are classed as spring flowers, although they are out before the end of August, and some

are out at the beginning of the month. This year the berberis has carried bunches of flowers, off and on, throughout winter. When does spring begin, anyway: That is a dangerous question, because nearly everyone has a different answer.

The early historian, Pliny, gave spring a maritime flavour: “. . . The spring openeth the sea for sailors; in the beginning whereof the west winds mitigate the winter weather at what time as the sun is in the twentyfifth degree of Aquarius, and that is the sixth day before the Ides.of February.” (Early August, here).

The ancient Greeks reckoned the beginning of spring by the evening rising of ' Arcturus, which happened 60 days after the winter solstice, and celebrated the occasion with a big festival at which they wreathed themselves with garlands of brilliantly-coloured anemones. That would be August 21 in our hemisphere. In the eighteenth century the Encyclopedia Britannica defined spring as beginning when the sun entered the first degrea of Aries, about March 10 (September 10 here). That may not be far out. Official New Zealand spring as laid down in Weather Office regulations begins on September 1, though many gardeners regard August 1 as the first day of spring. I prefer to consider it spring when significant growth is visible in the garden, and this is usually about the third week of September. This dating would correspond with that laid down by E. A. Bowles, the great English gardener, author of three famous books dealing with his own garden in the different seasons, and for many years chairman of the Royal Horticultural Society’s scientific corrtmittee.

His view was that spring begins when the long-term daily average temperature reaches 48 deg. F (9 deg on the present scale), and in London that happened on April 15. Our own spring, by that definition, begins a month earlier, in mid-September, putting us on a par with, say, Venice. If the rain that is falling outside as I write these notes does not stop soon we may have more in common with Venice than a date — we may need gondolas to get about.