Spring starts officially at the beginning of March, but of course, it can still be cold and frosty and around the time of the equinox (equal day and night) on 21st/22nd we can experience â€˜mad March windsâ€™. This changing of seasons is caused by the earth tilting on its axis as it orbits the sun. For those of us in the northern hemisphere, the north pole is further from the sun during winter and as it tilts in summer, more of the northern hemisphere is exposed to more direct rays from the sun.
What this means in the world of nature is that, around the countryside and parks, dormant plants and trees are waking up. A pale green tinge appears on the bare spikes of trees as buds begin to open. As the leaves unfold, water is sucked up from the roots and the process of photosynthesis begins. Food reserves from bulbs and roots are used up and new food is manufactured in the leaves. Energy from the sun is absorbed by chlorophyll, the substance which gives plants their green colour, and combines with carbon dioxide to produce starch. Incidentally, this ability of trees and plants to use carbon dioxide makes them ideal air purifiers. But they can only take so much!
You will see catkins of the willow, hazel and elm, while blackthorn is one of the first hedges to produce white flowers. In the parks, bulbs which have been planted will be visible, benefiting from the storage system that is the bulb. A crocus, by the way, grows from a corm, which is a swollen part of the stem, rather than a bulb.
As snowdrops fade, crocuses in various bright colours appear, opening in the sun but remaining closed during dull days, followed by drifts of daffodils. Coltsfoot is another yellow flower that pops up in waste grounds but shouldnâ€™t be mistaken for the dandelion. The flowers are similar but the stems and leaves are different. The dandelion has a smooth hollow stem while the coltsfoot stem has pink scales pressed against it and the leaves appear only after the flowers have faded.
Primroses, oxlips and cowslips are not seen so often and are also quite similar. The way to recognise the primrose is that each flower grows on its own stem while cowslip and oxlip flowers grow from the top of a single stem.
Wood anemones grow from bare woodland floors between the end of March and May. The stem grows then, at the top, the leaves spread in their efforts to catch the light before the tree canopy thickens. A single flower appears with sepals but no petals. Also in the woods, bluebells make a blue carpet and lesser celandine, primroses and greater stitchwort add yellow and white to the increasingly bright palette.
Trees which produce catkins get off to a good start. Both male and female catkins produce nectar to attract insects, which then carry the pollen from flower to flower. These catkins have amusing nicknames. â€˜Pussyâ€™ willow is the name of goat willow or sallow, so called because of their silver furry feel.
Hazel catkins (above and left) are known as â€˜lambâ€™s tailsâ€™ partly because of their appearance and partly because they appear at lambing time. Alongside them are buds with a red tassel, which is the female flower. The common oak also produces catkins, which grow in bunches along the stem. Willow and poplar trees produce either male or female catkins, but all the other catkin producing trees bear both sexes on the same branches. Hazel catkins will be the first to appear, followed by those of the silver birch. Female catkins appear later and form winged seed pods. Beech catkins hang in yellow â€˜pom-pomsâ€™ at the end of stalks.
Flowering in early spring is an advantage, as there are no leaves to prevent wind blown pollen from floating away, but pollination by wind can be a haphazard business, with the feathery stigmas of the female plants trying to trap the pollen as it flies by. Furry catkins, which are pollinated by insects, enjoy a more reliable method of fertilisation. This early in the season, they provide a valuable and much needed source of early food for bees.
Pollen grains, incidentally, have been found thousand of kilometres out to sea. They are all unique and can be identified when they are found preserved in bogs and other places. When these bogs are excavated in layers, the grains from the pollen found in them can be analysed and this is how we know that the first trees to arrive after the last Ice Age were willows and birches, followed by hazels, elms and oaks.
In wilder, grassy areas, fields fill with clover, yarrow (pictured left), ribwort, plantain and dandelion which all feed grazing animals, but buttercups, perhaps surprisingly, are poisonous. In damper conditions, marsh marigolds and fritillaries may be found. With most grasslands now ploughed and drained to grow crops or pasture, your best chance of seeing these meadow plants is in the country parks or on roadside verges.
Rabbits, too, can change the vegetation, as they will graze on gorse and heather as well as grasses. They will keep your lawn trimmed very neatly but they will also trim other plants in the vegetable garden that you might want to keep.