Opinions are divided as to whether the loganberry is a red-fruiting form of the common Californian blackberry, Rubus ursinus vitifolius, or a seedling from a cross between the ‘Red Antwerp’ raspberry and the American blackberry `Aughinburgh’. The plant appeared in 1881 in the garden of Judge J. H. Logan of Santa Cruz, California, from whom it takes its name. It has been cultivated in England since 1897.
The loganberry produces vigorous, prickly canes carrying 3- to 5-lobed leaves. As flowering is late, the plants may be grown in low-lying situations; spring frosts rarely damage the blossom, though severe winters may affect the canes. Loganberries are self-compatible and yield heavy crops of blunt, firm, very juicy, deep red berries of a rich flavor, from August to September. The yield may be sustained for 15 years or more. The berries do not plug, so are picked complete with core. Picking is best done when the berries are quite dry.
Heavy, rather than chalky and light and dry, soils are preferred—chalky soils induce iron and manganese deficiencies. Well-drained loarns and brick earths are ideal. Loganberries love rich soil and respond to generous manuring. Nitrogen is the most important plant food requirement. Mulch annually with farmyard manure in late autumn or feed with 56g (2oz) of fish manure and 28g (loz) of sulphate of potash per sq m (sq ft).
A sunny and open but sheltered site is best with protection from north-east winds. The rows should run north-south.
Propagation is usually by tip-layering between June and mid-August. The tips of young canes are pegged down 6-8cm (2-3in) deep (or weighted with a flat stone), into small pots filled with a rooting compost and sunk in the ground. The young plants are severed from the parent canes when well-rooted in the following February. Alternatively, leaf bud cuttings are rooted 6cm (2in) apart in a bed of sandy soil in a closed and shaded garden frame in July or August. Each cutting consists of a leaf and bud with a 2.5cm (lin) length of cane bark devoid of pith. Roots are produced in three to four weeks; the young plants are hardened off a month later and transplanted the following spring.
Rooted tips or cuttings are planted 2-3m (6-10ft) apart in February or March against fences, north or east walls, and up arches. Post and wire supports with wires at 0.6, 1.2 and 2m (2, 4 and 6ft) from soil level are used on open sites. Shorten the young plants to 23cm (9in) after planting, to encourage the production of strong new shoots on which fruit will be borne the following year. To reduce disease infection from the older canes, the young canes are trained fan-wise on the opposite side from the old canes. The two ages of cane occupy alternate sides annually. Ten to 12 fruiting canes are retained per plant. Fruiting is on one-year-old canes which are cut down to ground level in October after fruit harvest.
Pests and diseases are the same as those which attack raspberries.
Two good varieties are the following: `LY 59′, which is a virus-free clone available since the late 1950s. It is free from the debilitating viruses which reduce the crop of infected loganberries. It is the heaviest cropper—it may yield 8.5kg (17 1/2lb) of fruit per bush. ‘American Thornless’, a prickle-free mutation was found in 1933. It is a pleasure to prune. Slightly less vigorous than the common loganberry, it is an ideal variety for the smaller garden and may yield up to 7.5kg (15lb) of fruit per bush.
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