The common walnut, Juglans regia, is not a native tree. It was probably introduced to Britain from Persia by the Romans. But it seems to like it here, making an imposing and handsome forest or specimen tree that produces delicious nuts and provides a timber that cannot be bettered for fine cabinet and veneer work.
In Northamptonshire, where I live, they are quite common in country gardens, churchyards and on farmland. Although I assume that almost all are unnamed seedlings some bear crops of good walnuts.
According to enthusiasts like Clive Simms, anyone in England, or even southern Scotland, with a reasonably-sized garden could plant a walnut, provided that it is sheltered from cold winds and not subject to spring frosts.
Over the past 20 years Simms has grown a number of unusual cultivars, introducing some from abroad - not to mention chestnuts, mulberries, figs, apples, pears, medlars and quinces.
He grows them all in tall flexible pots in a small nursery behind his house in rural Lincolnshire and also, thanks to a friendly farmer, in local hedgerows and along dry stone walls. The orchard, he says, "is about a mile long, in straight lines".
His interest was kindled when, as a biology teacher, he was put in charge of rural studies and had the run of heated greenhouses in which to experiment with tender fruits. When he gave up teaching he taught himself to graft rootstocks so that he could produce sellable named varieties of walnut whose characteristics (unlike those of seedlings) were known to him.
He has since tended to concentrate on cultivars that start cropping in about three years, have good-quality nuts that "shuck off" the staining fleshy skins, are disease-resistant, at least partly self-fertile and are late-leafing to limit spring frost damage.
He recommends 'Broadview', 'Buccaneer' (a good pollinator), 'Hansen', 'Rita', 'Number 26' and 'Number 139'. Also worth considering are 'Fernor', 'Franquette' and 'Ferjean'. Simms has recently published what he calls a "cheap and cheerful guide", but I would call it a useful and concise booklet on growing walnuts. He plans to follow this up with others in the same format on mulberries, figs and other fruit trees.
Walnuts for pickling are picked in late June, when it is still possible to put a skewer right through them but October is the moment for harvesting the nuts - crows and squirrels permitting.
If the husks have not shucked off completely they should be removed, Simms says, using rubber gloves to prevent the nicotine-brown staining, and the nuts cleaned. They should then be dried quite quickly: Simms puts his in open trays next to the woodburner.
As for "A woman, a dog and a walnut tree; the harder they are beaten, the better they be", he thinks the phrase originated on the Continent where long poles were used for harvesting nuts. These knocked down both the walnuts and any dead branches, limiting the spread of fungal infections. This beating would have also stimulated late-summer shoot formation - useful for a plant that flowers at the tips of stems formed the previous year.
In time Juglans regia reaches about 56ft (17m) tall with a very broad spreading crown. The leaves are large and compound, with five to seven scented leaflets.
The male and female catkin flowers appear separately in late spring, the males being showier and up to 4in long. Walnuts cannot be said to be truly self-fertile, because these often mature at slightly different times. The fruit are oval, with a glossy-green fleshy husk, which shucks off to reveal the familiar hard shell, protecting a convoluted kernel inside.
How to grow
Walnuts do best on deep, moisture-retentive, alkaline soil and in a sunny but sheltered position. They should be planted sufficiently far from other trees so that squirrels cannot leap into the branches, and away from paths, which husks can stain and make slippery. To help fertility it is sensible to plant a tree within 100m of another.
They should be planted, preferably small and bare-rooted, in November or February. Formative pruning should aim for a 6.6ft (2m) clean trunk, with three or four branches above. Wounds bleed profusely if they are pruned after January. Walnuts benefit from mulching, nitrogenous and potash fertiliser in spring and water in dry seasons.
Pests and diseases
Walnuts are prone to disease in wet seasons, especially leaf blotch - which is common but not too serious - and walnut blight, which is more serious and most affects areas of high rainfall. The worst pest is the squirrel, which will take walnuts before they are ripe and which Simms deters with baffles - overlapping thin sheets of shiny aluminium, about 3ft (1m) long, nailed to the trees about 5ft (1.5m) from the ground.
Where to buy
Clive Simms has very limited stock to sell mail order, so suggests the following sources of walnut cultivars:
Grafted Walnut Trees, The Manse, Capel Isaac, Llandeilo, Camarthenshire SA19 7TN (01558 669043; www.graftedwalnuts.co.uk). Catalogues cost 3 x 1st-class stamps. Rarer varieties and cultivars are sold on a first-come-first-served basis so early ordering is recommended.
Agroforestry Research Trust, 46 Hunters Moon, Dartington, Totnes, Devon TQ9 6JT (01803 840776; www.agroforestry.co.uk). Catalogues cost 4 x 1st-class stamps.
For a copy of 'A Nutshell Guide to Growing Walnuts' by Clive Simms, send a cheque for £2.99 to Orchard House Books, Woodhurst, Essendine, Stamford, Lincs PE9 4LQ