Dr Terry Mabbett explores the spring-flowering plants that litter the woodland floor.

WARMED by sunshine and refreshed by showers, April is the month when many trees re-foliate and flower in earnest, though some species will not move until way into May. Reluctance to re-foliate does not depend on whether a tree is native or exotic. Now is the time for those perennial, spring-flowering plants on the woodland floor – the bulbs, corms, tubers and rhizomes – to stir from their subterranean slumber before a new foliar canopy excludes them for another year.

SUNSHINE AND SHOWERS

Hawthorn is first tree out of the blocks. Miles of skeletal, see-through hedgerows will be transformed in days to give early nesting birds – the blackbirds, song thrushes and hedge sparrows – protection from predators’ prying eyes. Extension growth is phenomenal with up to a foot of new shoot and leaves by the time May arrives. Native hawthorn (common hawthorn – Crataegus monogyna and Midland hawthorn – Crataegus laevigata) is the most common woody plant across the British Isles.

Not far behind in timing and growth rate is native English oak (pedunculate oak – Quercus robur and sessile oak – Quercus petraea), the chunky brown buds breaking in mid April. Within 14 days, each bud will have produced around 10 new leaves plus male and female flowers, the former yellowish-green, pendulous catkins and the latter tiny, pinkish, round flowers in the leaf axils.

Forestry Journal: Wild garlic (ramsons) provides a powerful sight (and smell) of spring.Wild garlic (ramsons) provides a powerful sight (and smell) of spring.

Even more staggering is the accompanying increase in oak leaf area. Measurements made on the first day of May will show leaf area has increased by a factor of 10 in just two weeks.

Fast out of the winter trap is white flowering horse chestnut, an exotic species brought to these islands 500 years ago. Aesculus hippocastanum is at home in the much warmer Balkan states and Turkey, although it is apparently not deterred from its intrinsically early re-foliation. By April’s end the drooping branches drip with large hands of palmate-arranged leaflets. The candelabra-like inflorescences are white and speckled with red and yellow to reveal a more exotic origin than the British Isles. However, it’s equally exotic namesake sweet chestnut (Castanea sativa) is showing no signs of reproducing. Yellow, male catkins with female flowers at the base will not appear until June or July, one reason why fully formed, ripe chestnuts in October are relatively rare.

READ MORE: March of the months and the sweet smell of spring

However, a short season is no problem for the truly native common ash (Fraxinus excelsior), with re-foliation relegated to the second half of May. Its inconspicuous flowers, with male and female flowers invariably on separate trees (dioecious), will not be ready to donate and receive pollen until May, even though the flower buds will have burst in early spring. Despite its late start, common ash completes its life cycle well in time, being the first native tree to drop foliage in September and leave bunches of ash keys (fruits) rattling in the wind through winter.

Forestry Journal: If one single species signifies spring, then that tree is the wild cherry or gean when in full bloom.If one single species signifies spring, then that tree is the wild cherry or gean when in full bloom.

The beautiful and bountiful blossom on wild cherry or gean (Prunus avium) is anything but inconspicuous. Indeed, if a single tree species symbolises spring, then wild cherry, immortalised down the ages in poetry and prose, is that one. The transformation of the trees from bare branches to brazen blossoms may happen during a single morning if the April sunshine is sufficiently strong. By the same token, the flowers will not last long, but cherry blossom looks best when the sun is strong, so short, sharp and sweet is perhaps the best outcome. New leaves sneak out just behind the flowers to shield bunches of tiny young cherries from wood pigeons.

The popular view, backed up by phenology, says trees are re-foliating and flowering significantly earlier under the influence of climate warming. That may be so, but I still keep 16 April as the day when wild cherry is in full flower (Home Counties), and apart from very early springs (like 2020) trees have been true to form for the last three decades.

SPRING FLOWERS IN WOODLAND

Things are happening thick and fast on the ground as well as in the tree canopy. If spring in the trees is a white affair, then on the ground it is often yellow. Dandelion rosettes, having withstood the worst of winter through deep-seated tap roots, are sending up bright yellow composite flowers in profusion. This sudden mass of vivid yellow is the first of two crops of flowers which, as winemakers know, is best for the forthcoming brew.

Forestry Journal: Moschatel, with its green petals and historically regarded as ‘of no account’, was still a joy to find amongst the hazel coppice.Moschatel, with its green petals and historically regarded as ‘of no account’, was still a joy to find amongst the hazel coppice.

Food stored in the bulbs, corms, tubers and rhizomes of spring-flowering plants is now in full flow as these native species flower under trees with which they have co-evolved. Delicate, dainty and damp-loving are the white flowers of wood sorrel or fairy bells (Oxalis acetosella). Wood sorrel is traditionally tied to beech woods, to an extent that rotting beech stumps are quoted as the plant’s favourite niche. However, Oxalis acetosella, with its tiny rhizomes (underground stems) as food storage and survival organs, is one of the few forest-floor plants that can survive in dense-canopied conifer plantations.

Indeed, I have encountered huge swathes of these trifoliate plants in Scots and Corsican pine plantations – even under the towering coast redwood trees at Leighton, near Welshpool in Powys, North Wales. That might indicate an acid-loving species, though a close connection with beech would suggest the opposite; a preference for an alkaline, chalky soil where beech is traditionally found in southern England. A clue may come from Norway, where ecologists curious and concerned about yellowing leaves and general ill-health of wood sorrel growing under Norway spruce found liming the soil cured the problem, although this is of little benefit to the acidophilic conifer.

READ MORE: Trees in February Fill-Dyke

Also white, dainty and delicate is the wood anemone (windflower), called the ‘flower of death’ by the Chinese because of its pale, ghostly appearance. It is similarly regarded as an unlucky flower in Britain because the flowers close up when it rains. Folklore says the fairy folk hide in the flowers to shelter from the downpour. Wood anemone is quite cosmopolitan in its taste for woodland tree mixtures and soils, and may even be found on chalk downland without a tree in sight. However, hazel coppice is definitely a preferred habitat.  Snow-white drifts of wood anemones appear from nowhere in the first or second spring after hazel has been cut, the underground rhizomes responding rapidly to increased light.

Bright yellow lesser celandines (Ficaria verna) and the paler yellow primroses (Primula vulgaris) break up the white drifts of wood anemones. Both thrive in well-lit clearings and along woodland rides, apparently indifferent to the nature of the climax trees that tower above, whether they be ash, oak or beech. The first flowering primrose (prima rosa), like first sighting of the swallow, is a traditional milestone and marker for spring. Having two distinctly different flowers – pin-eyed and thrum-eyed – is a peculiarity of the primrose.

Forestry Journal: Despite originating in much warmer climes, white flowering horse chestnut is one of the first ‘runners out of the blocks’, despite the risk of late frosts.Despite originating in much warmer climes, white flowering horse chestnut is one of the first ‘runners out of the blocks’, despite the risk of late frosts.

Damp-loving lesser celandine persists by root tubers but spreads via tiny bulbs (bulbils or tubercles) in the leaf axils. Despite the universal association of William Wordsworth with wild daffodils – ‘I wandered lonely as a cloud’ – the poet’s favourite flower was the lesser celandine, about which he wrote three poems (ironic, given the lesser celandine’s alternative name ‘pilewort’, according to the ‘Doctrine of Signatures’, because the tubers are shaped like haemorrhoids).

So great was Wordsworth’s love for lesser celandines that a stonemason was asked to engrave the flower on the poet’s tombstone. Unfortunately, there was a mix-up and a completely unrelated namesake, the greater celandine of the poppy family (Papaveraceae), was engraved instead.

Lesser celandine is damp-loving, but not as much as the bigger marsh marigold (kingcup), or ramsons (wild garlic, Allium ursinum). Like lesser celandine, marsh marigold (Caltha palustris) belongs to the buttercup family (Ranunculaceae), but this much bigger plant likes much wetter woodlands where the alder, sallow and willow reign supreme.

Last and, despite its obscurity, definitely not least is the rhizomatous moschatel (Adoxa moschatellina), a low-profile plant with yellow-green flowers that fail to compensate for its low stature. The Latin name is derived from two Greek words, ‘a’ used as a prefix to bestow privative status and ‘doxa’ meaning opinion, signifying a plant of no account. It is nevertheless a joy to find amongst hazel coppice in spring.

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