There are 21 fruit trees, planted by the wall . . .

Gardeners can just about get away with planting fruit trees in this colder than normal weather

ACCORDING TO a recent report from Met Éireann, it’s been the coldest, frostiest winter in Ireland for almost 50 years, and the coldest February since 1986, with air temperatures last month an average of two degrees below normal. It’s no surprise, then, that spring has been painfully slow in coming to the OPW’s restored walled kitchen garden in the Phoenix Park.

As a result (with the exception of parsnips which they sowed several weeks ago), OPW gardeners Meeda Downey and Brian Quinn have been very wary of sowing seed either outdoors or in the heated glasshouses. The risk is that any young plants raised early will then get hit hard by late frosts. “I wouldn’t even have sowed the parsnips if I’d known that it was going to stay as cold as this,” says Brian with a sigh. But one small advantage of this colder-than-normal weather is that the gardeners can still (just about) get away with planting fruit trees in the garden.

And so a delivery last week from both the Wexford-based English’s Fruit Nursery (Coonogue, Adamstown, Co Wexford, tel: 053-92340984/ 9240504) and Reads Nursery of Norfolk (readsnursery.co.uk, tel: 0044-1508548395) left Brian and Meeda racing to get the young trees into the ground before they start into growth.

It included five fan-trained Morello cherry trees for the north-facing wall (this acid cherry will grow quite happily in some shade) and a selection of damsons, bullaces, plums and pears for both the cool east-facing wall and the sunny, warm west-facing wall.

Unfortunately for the OPW gardeners, the south-facing wall (one of the best for many fruit trees) is off-bounds, as it’s in this end of the garden that the much-anticipated, restored Jacob Owen glasshouse will eventually be re-instated.

“A hot, sunny south-facing wall would have been great, particularly for the pears, but we don’t have that option. Instead it’s been a bit of a balancing act, but we’ve decided to plant the eight Victoria plum trees along the east-facing wall as they don’t need as much heat as the other varieties to ripen,” explains Meeda.

“The damsons will go to the shadier end of the west-facing wall, with the pears to the sunnier end as they’re hardest to ripen.”

In total, the gardeners are planting 21 young fruit trees along the old, toffee-coloured brick walls that enclose the kitchen garden, including cordon, espalier and fan-trained varieties.

All will eventually be gently tied to wall-mounted wires to keep them ship-shape, but in the meantime the gardeners are leaving in place the “training structures” of bamboos and plastic-coated wire, which came with the young trees.

Later on in the year, the complicated ritual of pruning and training the new growth will begin. Even now, with temperatures still dropping below zero at night, the old brick walls will act like primitive storage heaters, protecting the young trees from the worst of harsh frosts. They’ll also help later on in the year, when it’s time for the fruits to ripen, by storing the warmth of the summer sun.

Some of the fruit varieties that the OPW gardeners are planting, like the self-fertile Victoria plum, are familiar to them, while others, like the bullace, a close relative of the plum, are less so. Also known as the wild damson and similar to the blackthorn or sloe, the blue-black fruit of this tree "is found growing wild in hedges near orchards and gardens from which it presumably escaped years ago", according to Roger Phillips, author of Wild Food, who adds that the damson is probably a cultivated form of this fruit. In his best-selling book, The Fruit Expert, author Dr Hessayon dismisses the bullace, baldly stating that although you might eventually find a supplier "it really isn't worth growing". But Brian and Meeda are curious to find out for themselves.

Even if they discover that they agree with Hessayon, the gardeners won't be too disappointed as they're also growing the classic damson variety, Merryweather, a large, juicy, acidic fruit with blue-black skin and yellow flesh which (in contrast to its damning description of the bullace) The Fruit Expertdescribes as "an excellent all-round performer".

Along the west-facing wall, Brian and Meeda are also planting two specimens of Kirke’s Blue, a dessert plum with large, juicy purple-blue fruits that’s been cultivated since the 1820s when it was first sold by Joseph Kirke at his Brompton Road Nursery in London.

And then there are the espalier pears, to which Brian and Meeda have given the warmest, sunniest spot available. But when you discover that the two varieties the gardeners are growing are rather grandly called Doyenne du Comiceand William's Bon Chretien, it seems only fitting that they should get such a privileged place in the kitchen garden. And given the fact that pears hate cold easterly winds, love/need sun, and are martyrs to frost (they flower so early that the blossom is often damaged, leading to poor harvests), it's no wonder that the gardeners are taking extra special care. "They're temperamental and tricky to grow," says Brian, who has his doubts that the trees will successfully produce ripe fruit, given the poor summers of late.

Like so much of gardening, it will be a case of wait and see. In the meantime, the gardeners will do all they can to help the trees along by digging deep planting holes and top-dressing them with manure and a few handfuls of the slow-release organic fertiliser OSMO. They’ll also be keeping a careful eye on the young trees during any future dry spells, as the young root balls take time to grow and develop.

Other urban farmers with less space might consider growing a pear, plum or damson tree in a large container (at least 45cm in diameter). If so, use a variety with a dwarfing rootstock so that it doesn’t get too large (look out for Quince C rootstock for pears, or Pixy/St Julien A rootstock for damsons/plums).

The Royal Horticultural Society’s website, rhs.org.uk, lists suitable varieties for container growing, including the aforementioned dessert plum Victoria as well as Blue Tit and Opal, all of which are self-fertile.

Suitable pear varieties include Doyenne du Comice, Conference, Concorde, Glou Moreau, Red Comice and Beurre Hardy. You'll need to grow at least two of these pear varieties for successful pollination/fruiting, and remember that they need a warm, protected, sunny spot. Which, after the harsh winter we've just endured, is something that we urban farmers would now like for ourselves.

• The OPW's Victorian walled kitchen garden is in the grounds of the Phoenix Park Visitor Centre, beside the Phoenix Park Café and Ashtown Castle. The gardens are open daily from 10am to 4.30pm

• Next week Urban Farmerin Propertywill cover sowing seed in a glasshouse

• Fionnuala Fallon is a garden designer and writer