Juglans, walnut tree; Carya, hickory , Nux juglans. A large tree which is cultivated for its fruit in the South of Europe. Some species may also be found in North America, but they differ so greatly from our walnuts and from each other that they will be treated separately. The European walnut grows a stem which is rarely straight but attains a great height and breadth. [1] The crown is furnished with a large number of broadly- spreading boughs. The roots are long, strong, and commonly taprooted, but not very fibrous. The bark is green on the shoots of the first year becoming brown the following year and lightening gradually over the next two or three years to become whitish and ashen: it is smooth until it is 25 or 30 years of age when it begins to fissure markedly, which tarnishes the colouring. The large, pale-green leaves exude a pungent, unpleasant odour: they are 5-, 7-, 9-, and sometimes 11-foliolate when the tree is in its first youth and vigour. At the end of April, the tree produces a large number of long, pendulous catkins. The fruit appears separately from the catkins towards the middle of May, on the new, feeble shoots. This fruit is the walnut, which is well known. It is enclosed in a woody shell which has a green, fleshy covering called a walnut husk. This hardy tree propagates readily, grows promptly, and is so useful that one may make use of all of its different parts.

The walnut thrives in mountain gorges and hillsides, in sites of a northerly or easterly exposure. It withstands the cold better than extreme heat. It thrives best in soil mixed with scree, gravel, or sand and generally in the same soil as the vine, provided that it is deep and cool. This tree grows well in mould, marl or chalk and all wheatlands, and has been known to thrive in tufa, where its roots penetrated to a depth of seven feet. I have raised it from seed in hard, heavy soil in clay which was somewhat damp, but it grew far more slowly. One may say that this tree generally thrives anywhere but that the richer the soil, the more cultivation it will require. Moreover, it cannot tolerate meadows, habitually-damp land, and soil planted with sainfoins, lucernes, etc. I have even seen strong, vigorous trees decay in three years when sainfoins were planted in their midst, and when the landlord destroyed this grass the trees regained their vigour in the same period of time.

There is only one method of propagating walnuts, which is by sowing the nuts. If the trees are being raised only for their wood, the nuts must be sown in the site in which they are to be cultivated, because if they were transplanted their taproots would be destroyed and they would no longer grow. If on the other hand they are being cultivated for their nuts, they must be transplanted several times: by this means, one will procure a greater supply of finer nuts more quickly. The nuts may be sown in autumn or spring: they are ripe when they begin to fall from the tree, at which point one must pick them and select those which have soft, white shells. If they are to be sown in autumn, they should be shelled and left to sweat and exude excess moisture until the end of October or the beginning of November. If one decides to sow them in spring, they may be stored with their pericarps in sand until the end of February or until the soil is ready to be worked. If one were to delay sowing by one more month, the germinating nuts would begin to burst or dry up. At least half of them would fail if they were not stored in sand in winter, but in this case one may soak the nuts in water for two or three days and reject those which float on the surface. The nuts are sown in cultivated soil to a depth of two or three inches using a picket, at intervals of eight or ten inches in rows two feet apart. At the end of two years, and certainly no later than three, one must transplant the young seedlings, in order to remove their taproots and oblige them to grow lateral roots which will enable them to take root again more readily when they are permanently transplanted. I have often seen walnuts of six or seven years of age which had never been transplanted and had only their taproots, with the result that none of them took root again. One must therefore transplant them after two or three years, without touching the tops, into another part of the tree nursery at intervals of 1½ feet in rows 2½ or 3 feet apart. After three or four years, when they are seven or eight feet tall, they may be permanently transplanted. Autumn is always the best season for this operation. When uprooting the seedlings, one must prune the roots sparingly, shorten them moderately, remove only the lateral shoots, and above all leave the tops intact. They must be tended for three years before being left to grow freely. Transplantation slows down the progress of the trees: a walnut raised from seed will in a few years have outgrown a transplanted walnut of ten years of age. Walnuts begin to bear fruit after seven years and are full grown after approximately sixty years.

It has been claimed that walnuts may be grafted on to each other, though it is admitted that flute grafting is the only suitable method and that success is not always certain. See the recommendations of M. Cabanis, who conducted several experiments on grafting the walnut, in the Journal de Verdun of March, July, and September 1739. [2]

The walnut, far from being subject to attack by insects, has on the contrary the virtue of repelling them. It is claimed that the shade of the tree is detrimental to people and plants: weak, fragile people can get headaches from the powerful odour of the leaves, whereas plants suffer more from the dripping of the leaves which contaminate water with a bitter, oily sap which is harmful to plant life. Because of their strong boughs and vigorous growth, walnuts cannot tolerate the proximity of other trees. They are so broadly spreading that they must be planted at intervals of thirty or forty feet. When they are planted in ploughable land, their roots pose no obstacle to the plough. It is claimed that ashes are the only suitable fertilizer for walnuts. If one taps the tree in spring, one can drink the sap which flows freely from the incision.

Walnuts have a great number of uses: everyone knows that their nuts are edible and that green walnuts are preferable to dry walnuts which are hard, oily, unwholesome, and hard to digest, though an oil may be extracted from them which has a variety of uses. The older the nuts, the more oil they give, but of a poorer quality than when it is extracted as soon as the nuts are dry. Dyers use the roots, bark, leaves, and husks to dye material fawn, coffee, or hazel coloured. To this end, they use the root before the sap begins to rise in the trees, the bark when the sap begins to flow, the leaves when the nuts are half ripe, and the husks when the nuts are green. The nuts are preserved, made into a wholesome ratafia, and roasted in sugar. Lastly, the powdered catkins, decocted leaves, and oil have some medicinal uses.

Walnut wood is brown, veined, solid, pliant, and easy to work. The wood of trees planted on hillsides and in mediocre soil is more veined and deeply coloured than the wood of those which have grown on flat areas and in good soil, and saplings are far less veined and coloured than mature trees. The ideal is for the trees to be l½-2 feet in diameter. Younger trees have a greater proportion of sapwood which is more subject to being worm-eaten, whereas the heartwood is very long-lasting, but one can prevent wormwood and make the sapwood as useful as the heartwood by soaking it in boiling walnut oil. When it is perfect, this wood is the finest of Europe. It was formerly highly regarded and the best-quality furniture was made from it before the discovery of America, from where infinitely more precious woods have been taken. This wood neither fissures nor warps: it is the best European wood for making funriture and when it is well veined it is also the costliest. The wood and roots are sought after by joiners, cabinetmakers, gunmakers, sculptors, coachbuilders, violin makers, turners, coopers, binders, morocco-leather dressers, etc. and the wood can also be used in shoemaking when it is quite dry. It makes a gentle fire but provides no charcoal.

There are several species of walnut, which are grouped firstly into European and American walnuts: the latter differ markedly from the former and even more markedly between themselves. [3] The productions of this part of the world are of infinite variety and merit the preference for beauty, ornamental interest, and singularity. However, their fruits are generally poorer than ours, which were themselves little better at the time of the Romans when they were small in number and of mediocre quality. We may therefore presume that when we have sown American seeds in different soils over the same period of time, we will obtain fruits of the same quality and variety as our own.

European walnuts.

1. English walnut: this species is the most widespread.

2. Large walnut: the leaves of this walnut are larger than those of other walnuts and the nuts are much larger. This tree grows more promptly and forms a larger tree, but its wood is less veined and coloured, and the nuts are good only when they are green or preserved: they are so soft that they wrinkle and shrink to half their original size when they are dry, which also alters their quality.

3. Thin-shelled walnut: this tree bears the finest nuts, of which the shells are white and easy to crack. These nuts should be preferred for sowing.

4. Hard-fruited walnut: the nuts of this tree are so small and hard that it is scarcely possible to crack them and even more difficult to remove the nut, which is suitable only for making oil. However, the wood of this tree is excellent: it is harder, stronger, more veined, and finer than that of any other walnut.

5. Walnut with serrate leaves: this is a medium-grown tree of which the leaves are smaller than those of the common walnut and the nuts longer.

6. Saint John walnut: this tree is so-named because its leaves begin to appear only at the beginning of June and it is densely covered only by the Feast of Saint John. [4] This singularity is not the only virtue of this precious tree: in several provinces of the kingdom, especially in Burgundy, other walnuts which shoot from the beginning of May are vulnerable to spring frosts which cause their fruit to perish, whereas since the Saint John walnut begins to grow only when spring is assured it does not have this drawback. Steps should therefore be taken to multiply this tree, of which the fine nuts ripen almost as soon as other walnuts.

There is also a small-fruited walnut, a walnut with lobed leaves, a cluster walnut, and a walnut which fruits twice a year, but these trees are so rare that they are never seen: they are found only in works of botanical nomenclature.

American walnuts.

1. Black Virginia walnut with long fruit. [5] This tree may also be found in Canada and along the coastline of North America. It is naturally ascending and grows to a great height. The bark is brownish and extremely smooth. The tree grows a large number of black roots covered with root hairs and is rarely taprooted. The leaves on the young trees are often two feet long and composed of any number of leaflets, commonly thirteen, but in some cases twenty-one. The leaflets at the centre of the petioles are longer than those near the tips: they are of a soft, yellow-green and are quite striking. The aroma which they exude is neither strong nor disagreeable. They begin to grow fifteen days earlier than those of the English walnut. The nuts also appear earlier: they are edible as green walnuts from the beginning of July and are perfectly ripe when they fall at the end of August. With their husks, they are usually 2½ inches long by 4 inches round. When they are fresh, the husks smell strongly of terebinth and instead of being smooth on the outside they are downy and sticky. The shell does not split: it is deeply furrowed and so hard that it has to be cracked with a mallet. One stands the best chance of preserving the nut by striking the top of the shell, but great skill is still required in order to extract the nut because the partition is as ligneous as the shell. The kernel is divided into no more than two parts at the centre, whereas English walnuts are divided into four. This tree is hardier than the English walnut and is rarely damaged by spring frosts, but it fruits later and yields less. It requires rich loam, and thrives in valley bottoms and dampish sites but cannot tolerate dry, elevated ground and soon decays in soil which is sandy or too superficial. The leaves fall early, from September when the season is dry. It is propagated in the same manner as the English walnut and does not need to be prepared for transplantation: it takes root again perfectly because it has so many roots and is rarely taprooted. The nuts often spring up only in their second or third year because the shells are so hard. This tree requires no cultivation: it is wilder and more uncultivated than the English walnut and would probably thrive in woods because it is naturally ascending: in his treatise on Louisiana, M. Le Page reports that there was a 150-acre timber wood of these trees on the land he was given. [6]

The green nuts of this tree are very palatable: they are pithy, less crisp, subtler, and easier to digest than ordinary walnuts, and are so well covered by their shells that they keep fresh until the end of winter. It is thought that the nut is black because the dry, resinous husk adheres to the shell at the furrows and blackens with age; however, some explain its colour by the black of the wood. According to the reports of travellers, particularly M. Le Page whom I have just cited, this nut gives a lot of oil and the indigenous population of Louisiana make bread from it.

The wood of this walnut is blackish, veined, porous, and brittle. However, it can offer some support, and is very durable in the ground and in water: it appears to be suitable for joinery and the products of cabinetmakers and turners.

There are already a large number of these trees in Burgundy which are beginning to fruit and there is reason to believe that it will soon become widespread there.

2. Black Virginia walnut with round fruit: this walnut differs from the preceding tree only in the shape of its nuts. I have only a single seedling of this tree which has not yet fruited even though it is over twenty years of age. According to Miller, this tree yields well in England. [7]

3. White Virginia walnut, or Hickory. [8] A small tree which grows to only twelve or fifteen feet in France. It grows a straight, slender stem and throws out few lateral shoots, with the result that its crown is extremely small. When one touches the buds of this tree in winter, they exude a pleasant, fragrant aroma. The bark is rough and of a dull grey. The taproot is not fibrous. The leaves resemble those of the English walnut but are laced with a paler, more yellowish green and are not fragrant. The fruit resembles a small chestnut in size and shape: it has a smooth, brown, thin, dry husk and a white, smooth, softish husk. The kernel is white and tastes like a beechnut but is somewhat too astringent to eat. This tree is hardy and tolerates the cold more readily than warm weather. It thrives in mediocre soil provided that it is deep, in elevated ground, and especially on east- or north-facing hillsides. It will grow in loam in flat areas, but far more slowly. It does not take root again readily following transplantation unless its taproot has been removed at an early stage. I have several seedlings of this tree of eighteen years of age which are only 9-10 feet tall by about 3 inches round and have not yet borne fruit. The wood of this tree is white, dense, quite hard, and very pliable.

There are many varieties of this tree in North America: I have seen seven different nuts from this tree ranging from sweet to sour and with shells which were more or less bony, thick, and smooth. A number of hickories are described in Catesby, but the descriptions are not sufficiently detailed for them to be clearly distinguishable. Although this tree is already widespread in England, it is still rare in France. [9]

Louisiana walnut, or pecan. [10] A medium-grown tree which is commonly found in the temperate climates of North America. It grows a straight stem and a spreading crown. The long roots have few root hairs and do not appear to be taprooted. The bark splits when it is twelve or fifteen years of age and becomes rough and uneven: it is of a dark, ashen colour. The leaves are usually from 1-1½ feet long: they are usually composed of fifteen leaflets, but when the tree is in its first vigour it sometimes grows leaves of up to three feet with twenty-one leaflets. These leaves have the same characteristics as those of the black walnut: the leaflets at the centre are the longest and broadest. Whatever M. Linnaeus (who has put this tree with the hickories, of which the leaves have an entirely different arrangement) may say, the leaves of the pecan are smooth, dentate, odourless, and of a bright, though dark, green. At first sight, this tree resembles the ash. The nuts, called pecans by the indigenous population, are shaped like olives: they are long, smooth, pointed at the tip, and 1½ inches or 2 inches long by 2 inches round. I have not seen the husks because they are always removed before shipping, which suggests that the nuts part readily from their husks. The hazel-coloured shells are so soft that they may be cracked between one’s fingers. The kernels are shaped like ordinary walnuts but are longer, less oily, and of a finer, delicate flavour closely resembling that of the hazelnut. Excellent pralines are made from them in America.

In our climate, at Montbard in Burgundy, this tree is hardy and springs up well, but seems little disposed to bear fruit: I have a pecan seedling which, though 23 years of age, 15 feet tall, and 4 inches round, has not yet produced even catkins. The leaves do not appear until the beginning of May and fall only after the first frosts. The leaflets are narrower, longer and more close set than those of the black walnut. When young the pecan takes root again readily following transplantation, but when it is mature it does not seem to strike root again readily and those which were transplanted when they were full grown did not put down roots. I have also ascertained that this tree thrives in good, dampish loam and a south-facing site halfway down a slope. This tree can be propagated only by sowing the nuts, of which the majority come up only in their second year.

Notes

1. Juglans regia, the English or Black Sea walnut, which will henceforth be referred to as the English walnut.

2. Jean-Baptiste Cabanis de Salagnac (1723-86) of Yssoudon is celebrated for having perfected the grafting of fruit trees. In 1764, he was crowned by the Académie des Sciences et Belles-Lettres of Bordeaux for a memoir which was published as Cabanis, 1764 ( Biographie universelle ancienne et moderne, 1842-65, vi.298).

3. There are twenty-one species of Juglans, of which Juglans regia, which may have originated in Iran and the Balkans, is the only European species. The other European walnuts listed are cultivars (Huxley et al., 1992, ii.719). See D. J. Mabberley, The Plant-book: a Portable Dictionary of the Vascular Plants (Cambridge, 1997), 373.

4. The Feast of Saint John the Baptist is 24 June.

5. Juglans nigra, the black or American walnut.

6. Le Page du Pratz, 1758.

7. Article ‘ Juglans ’, Miller, 1752.

8. Juglans and Carya (hickory) both belong to the Juglandaceae family.

9. There are fourteen species of Carya: the species described here is probably Carya glabra . See D. J. Mabberley, The Plant-book: a Portable Dictionary of the Vascular Plants (Cambridge, 1997), 130.

10. Carya illinoinensis.