© 2014 by Barbara Copperthwaite.

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The bravest of blooms

 

 

When winter’s grip seems at its strongest, some flowers appear to defy it to peek through and introduce a much-needed splash of colour. Now is the time to celebrate their delicate courage...

Snow and ice may lie on the ground still, yet apparently against all odds there is a flower blooming. The dainty snowdrop seems too delicate to survive the harsh conditions, its head bowed in apology at its own cheek, as it tries to blend into the background by mimicking winter’s white cloak.

It is very unusual in the plant world for flowers to bloom only in the middle of winter. Out of around two thousand flowering plants native to the British Isles, only a couple of dozen have a true flowering season in January and February.

Some plants will flower spasmodically all year round given favourable weather conditions – plants like shepherd’s purse, chickweed and Persian speedwell – but their peak comes in the warmer months when they are growing most vigorously.

To most people the true winter flower is the snowdrop: the first obvious flowers of the new year, they provide a very welcome sight.

Snowdrops begin to flower as early as Christmas in a mild winter, but if it is very cold they will wait until well into March. They were once rare in Britain, found only in the damp woods of western England, but today they are widespread, and for many are the key indicator that winter’s grip is loosening and spring is but a patient wait away.

To see them at their best, do not rise early. The flowers close at night and the next morning they do not open fully until around 10am, when the petals start to ooze out nectar. Because the petals droop the nectar is protected from rain. If you touch the tip of your tongue inside a snowdrop after it has been open to a few hours it tastes slightly sweet. The flower is a powerful attraction to the few early insects about at this time of year. Honey bees are sometimes seen to land on one of the spreading sepals, clinging to them with their hind legs as they delve into the flowers for pollen and nectar.

Snowdrops can freeze solid and then recover when they thaw. They do this by closing up to protect the reproductive parts and withdrawing water from their cell structure into the minute intervening air spaces. There ice crystals can form without causing any harm.

What’s more, these hardy plants create their own heat. You may notice places where plants have melted the snow immediately around them, and in some species flower buds as much as five degrees warmer than the surrounding air have been recorded. These higher temperatures are generated by rapidly growing plant tissues, although if the plant were to keep up these growth rates to withstand a prolonged frost it would quickly use up its food reserves

Snowdrops (above) produce their own heat. They and Winter Aconite (below) flower around at the same time, often while frost and snow are on the ground.

Early Small Tortoiseshell butterflies love the nectar from barren strawberry blooms.

and starve.

Spring snowflakes are rare relatives of the snowdrop. Similar to a large, robust snowdrop, the spring snowflake is easily recognised by its bell-shaped flowers with green tips to the petals. They come out a little later than snowdrops and are sometimes produced in pairs on the stem.

The first splash of real colour arrives with winter aconites, which come into flower at about the same time as snowdrops. Their flowers expand in sunny weather to reveal curious tubular petals which again hold droplets of nectar. Each flower is surrounded  by a leaf-like ruff, but the true leaves, which are highly poisonous, emerge from the ground only after the flowers have withered.

Introduced from Southern Europe four hundred years ago, the winter aconite has become widely naturalised. It is a type of plant known as a geophyte. Below the surface they store nutrients such as starch and sugar in order to be able to unleash their full glory the following year.

By far the commonest of our winter flowers, if not the most spectacular, is the barren strawberry, so called because it superficially resembles the true strawberry, but its fruit is hard and inedible. It too produces nectar (from a small five-sided nectary, a pad between its stamens and ovaries) and this is drunk by flies and beetles and even the occasional Small Tortoiseshell butterfly that has woken early from its hibernating sleep. It is easy to tell the barren strawberry from wild strawberry blooms: the petals of wild strawberries overlap slightly at their edges, but those of the barren strawberry don’t touch one another.

Another early riser is witch hazel. The bright yellow, orange and red hues of this shrub’s flowers can be seen from as early as January. Emerging bees are also grateful for the pale lilac blooms of winter heliotrope, which grows in damp hedgerows and on roadsides. The large, soft, spoon-shaped leaves resemble butterbur, a close relative. This species is introduced from southern Europe. It spreads by root fragments and is on the increase across the UK countryside.

Lastly, but not least, is the daffodil – and yes, Britain does have a native, wild-growing daff, as well as foreign species and their hybrids which have escaped gardens and established feral populations here. Gracing damp woods and grasslands, it is distinguished by demure nodding flowers, a tubular central corona with a narrow neck and wavy tepals. It is this daffodil which inspired Wordsworth to pen some of the most frequently recited lines of poetry in English language.

Most plants are dormant in mid-winter and wait until later to flower, when pollinating insects are abundant and the milder weather encourages growth. Although winter flowers have a monopoly of any insect that may be about, such as bees or flies, this is scarcely sufficient reason to flower now. So why do these particular plants expose their flowers to the rigours of winter?

Partly it is because they do not rely entirely on insect pollination for their reproduction and each plant can be fertilized by its own pollen. They also have root structures which can multiply and produce new plants – for example winter aconites have tubers, snowdrops and snowflakes have bulbs and barren strawberries have runners. However, plants only improve their stock if one flower is fertilised by the pollen of another, and with both these ‘do it yourself’ methods of reproduction the new plant is usually identical to the parent plant.  If cross-pollinated occurs, the next generation turns out slightly different from the parents, and consequently some plants ae perhaps better adapted to their environment.

The original environment of these plants may be another clue to their winter flowering. They occurred in the woodland which once covered Britain and Europe and adapted to this habitat by growing and flowering early in the year before the trees cut out their light. The temperature of woodland soil is considerably higher than that of the surrounding exposed land, and moss and dead leaves also acts as insulation.

Despite their delicate beauty, these flowers are tough and highly specialised – and a welcome sight after a long winter.