Deep fronds of root with myriad of defenders

ANOTHER LIFE:THE FROSTS have laid the hillside low, powdering the bracken, bleaching the rushes and combing the grasses into cow-licks of limp straw. But gardeners of the food-rearing sort can welcome a winter that takes a proper toll of aphids and allied pests, and crumbles lumpy soil into that ideal state for sowing, the "fine tilth" that all the books demand.

Frost has also levelled the weeds, but done anything to weaken the hidden networks of their roots. On my knees to rehabilitate a long-neglected vegetable bed, I felt a rush of sympathy for the host of new allotmenteers breaking fresh ground in their first spring outdoors.

Back at our own beginnings, I set out grasping the handlebars of a powerful, 13hp rotovator. Like some wild animal, it bucked and roared, snorting clouds of exhaust fumes as it churned into the stony soil. It was quickly abandoned in favour of a peaceful, contemplative spade, but not before it had sown half the field with self-generating fragments of marsh woundwort. This tall, crowding herb stores up its energy reserves in underground stolons like long, white cigars. They shatter at a touch, each little piece to grow anew.

Marsh woundwort is an unlikely suburban weed, but I share the more familiar cabling of couch-grass, Elymus repens. Its slender white hawsers just ask to be hauled from the soil, but for every exultant moment when a root delved for, foot after foot, surrenders itself intact, a host of struggles end in a mere snap and whatever is left will sprout again.

The quickest, easiest, non-organic answer is to spray with glyphosate. A glimpse of what arable farming was like before herbicides is in John Stewart Collis's classic memoir, The Worm Forgives The Plough. "You cultivate the field," he wrote, "drag it, chain-harrow it, pulling up enough couch to build a rick which you then burn in bundles and lines. But you can get more up – and then more. I refuse to use space in writing about it . . ."

But roots can get interesting, even in their great variety. I fight the claws that emerge from the end of the creeping buttercup’s shoots, or that anchor the tips of arching briars with a back-wrenching grip. I burrow after dark fronds of horsetail root, in the full futility of tackling a herb that can penetrate for 20m, releasing little cluster bombs of tubers at any attempt to haul it up. And then there are the deep, brittle fangs of taprooting perennials I introduced myself: ineradicable Russian comfrey, and the horseradish we will never be without.

We know that roots draw in food and water for the plant and give it firm anchorage. But research into the rhizosphere (the area immediately around the roots) is showing it to be busy with two-way traffic – indeed, multiple interlinkages between roots and the rest of the life of the soil: its microbes and myriad other organisms, as well as the roots of other plants.

More than 80 per cent of land plants, for example, have roots that depend on a partnership, or symbiosis, with tiny fungi called mycorrhiza. These supply inorganic nutrients from the soil in exchange for carbon from the plant’s photosynthesis.

The carrot is just one plant that exudes a substance from its hairy roots to trigger the fungal growth around them. Indeed, such exudates are thought to spark all kinds of interactions between plants and soil organisms, or between one kind of plant and another.

“Companion planting” has been a long-running refinement of the organic movement, drawing on traditional experience, on folklore and sometimes on rather dodgy science. Some plants seem to grow better together, others definitely don’t; some plants attract helpful insects, others repel pests. The more science learns about plants’ strategies for survival, and their hidden interlinkages, the sooner we shall know whether companion plantings that are “said to” work really do.

Some examples are provided in a leaflet, Allotments and Biodiversity, offered on the lively website of the South Dublin Allotments Association, homepage.eircom.net/~sthduballots.

The beneficial companionship of carrots and onions, to hide the smell of carrots from the dreaded carrot fly, is an old favourite (I prefer to use Bionet to keep the pest out), but this advice is also strong on introducing native wild plants to the allotment to attract companionable and beneficial insects – yarrow, for example, to bring insects to control aphids on the broccoli (not, it could be said, until the yarrow starts blooming in July).

Native hedges to bring birds to eat the snails and caterpillars are fine if there’s space for them, which adds point to the association’s plea for bigger local authority allotment plots. Forty square metres, apparently the current trend, is about the size of one modest polytunnel.

Eye on Nature

After the cold spell my kitten brought in several large, dead frogs. I thought frogs hibernated in the bottom of the pond.

Alison McCoy, Bantry, Co Cork

Mostly it is male frogs that go to the bottom of the pond. The large frogs could have been pregnant females out of hiding in dark places perhaps to spawn, and killed by extremely low temperatures.

A mistle thrush has been protecting its apple in our garden, seeing off any intruders. Four crows, a magpie, a blackbird and some starlings observed from a wire close by.

Pádraic Breathnach, Limerick

Mistle thrushes are renowned for this. One will defend a berried bush for weeks.

The annual feeding frenzy of bull- finches on the buds of my ornamental copper plum tree was in full swing on February 1st, with 15-20 black-capped russet beauties gorging at a time.

Jim Sutton, New Ross, Co Wexford

We have seen a very big, pelican-like, white bird flying along a drain that flows into the Blackwater. A great white egret?

Sarah Carey, Enfield, Co Kildare

Yes.

(On Jan 30th, Pete Mullineaux’s name should have appeared with the sighting of woodcocks, and Oonagh Duggan’s with the curlews on the family farm.)

Michael Viney welcomes observations at Thallabawn, Carrowniskey PO, Westport, Co Mayo. Email : viney@anu.ie. Include a postal address.