Soil and Situation. Walnuts will succeed in most soils that are not waterlogged, or very poor and liable to dry out severely in summer. Prefer open, sunny places.
Planting. As for apples. Space trees at least 30 ft. apart.
Forms of Training. Almost invariably grown as standards. Often planted for ornament as well as utility.
Pollination. Male catkins and female flowers appear on the same tree and are compatible. Unfortunately, some varieties produce female flowers years before the male catkins start to appear, and are therefore unfruitful for an unnecessarily long period. Other kinds bear catkins early and are useful for pollination. Most walnuts grown in this country are seedlings and, in consequence, very variable. It is not possible to say in advance to which type they will belong. Where possible, selected varieties chosen for their early production of catkins should be planted.
Pruning. Practically unnecessary except for the removal of badly placed branches to improve the balance of the head. This may be done in November.
Picking and Storing. Leave the nuts to fall naturally or shake them from the tree. Remove outer skins, wipe with damp cloth and store in earthenware jars or crocks with a layer of salt over each layer of nuts. If desired, dry coconut fibre or peat may be mixed in equal bulk with the salt.
Routine Feeding and Pest Control. Unnecessary.
Propagation. Usually by seeds sown outdoors in March. Better results are obtained by budding or grafting seedling walnuts with selected varieties. Budding is done outdoors in May or June, using a special method known as patch budding. The bud is cut out with a circle or rectangle of bark and a similar piece of bark is removed from the stock to receive it. Alternatively, young seedlings potted for the purpose may be grafted in the greenhouse, usually in February or March. A temperature of 60-65° must be maintained. Quicker results are obtained in a propagating case, temperature 70-75F. The grafted plants must be carefully hardened off for transference to a frame in May or June and planting in a nursery bed in the autumn.
Varieties. Franquette, Leeds Castle, Mayette, North-down Clawnut and Stutton Seedling.