|Rubus subsp. var.||Blackberry|
The blackberry is a widespread and well known shrub; commonly called a bramble in the eastern U.S. and Europe. (Genus Rubus, Family Rosaceae) growing to 3 m (10 ft) and producing a soft-bodied fruit popular for use in desserts, jams, seedless jellies and sometimes wine. Several Rubus species are called blackberry and since the species easily hybridize, there are many cultivars with more than one species in their ancestry.
The blackberry has a scrambling habit of dense arching stems carrying short curved very sharp spines (although many thornless/spineless cultivars have been developed), the branches rooting from the node tip when they reach the ground. It is very pervasive, growing at fast daily rates in woods, scrub, hillsides and hedgerows, colonizing large areas in a relatively short time. It will tolerate poor soil, and is an early coloniser of wasteland and building sites. It has palmate leaves of three to five leaflets with flowers of white or pink appearing from May to August, ripening to a black or dark purple fruit, the "blackberry."
Sometimes early flowers have form more drupelets than the later ones. This can be a symptom of exhausted reserves in the plant's roots, marginal pollinator populations, or where a small change in conditions, such as a rainy day or a day too hot for bees to work after early morning, can reduce the number of bee visits/pollen grains delivered to the flower, thus reducing the quality of the fruit. The drupelets only develop around ovules which are fertilized by the male gamete from a pollen grain.
In some parts of the world, such as in Chile, New Zealand and the Pacific Northwest region of North America, some blackberry species, particularly Rubus armeniacus (syn. R. procerus, 'Himalaya') and Rubus laciniatus ('Evergreen') are naturalized and considered an invasive species and a serious weed.
Pests and diseases
Redberry mite, a common pest of North American blackberry crops
The related but smaller European dewberry (R. caesius) can be distinguished by the white, waxy coating on the fruits, which also usually have fewer drupelets.
Illini Hardy a semi-erect thorny cultivar introduced by the University of Illinois is cane hardy in zone 5, where traditionally blackberry production has been problematic, since primocanes often failed to survive the winter.
Marion (marketed as marionberry) is the most important cultivar and is from a cross between Chehalem and Olallie (commonly called olallieberry) blackberries. It is said to "capture the best attributes of both berries and yields an aromatic bouquet and an intense blackberry flavor" . Olallie in turn is a cross between loganberry and youngberry. 'Marion', 'Chehalem' and 'Olallie are' just three of the many trailing blackberry cultivars developed by the USDA-ARS blackberry breeding program in Corvallis, Oregon. The most recent cultivars released from this program are the thornless cultivars Black Diamond, Black Pearl and Nightfall as well as the very early ripening Obsidian and Metolius. Some of the other cultivars from this program are Waldo, Siskiyou, Black Butte, Kotata, Pacific and Cascade. Trailing blackberries are vigorous, crown forming, require a trellis for support, and are less cold hardy than the erect or semi-erect blackberries. In addition to the Pacific Northwest of the USA, these types do well in similar climates such as the United Kingdom, New Zealand, Chile, and the Mediterranean countries.
Eastern, semi-erect blackberries were primarily developed by the USDA-ARS in Beltsville, Maryland. The source of thornlessness used in this program came from 'Merton Thornless' which was developed at the John Innes Institute in the United Kingdom. The semi-erect blackberries are thornless, crown forming, incredibly vigorous, and need a trellis for support. Cultivars of this type include the very popular Chester Thornless as well as Triple Crown, Loch Ness, 'Loch Tay', Smoothstem, Hull Thornless, Dirksen Thornless and Black Satin. Recently, the cultivar 'Cacanska Bestrna' (also called "Cacak Thornless") has been developed in Serbia and has been planted on many thousands of hectares there.
The University of Arkansas has been at the center of developing cultivars of erect blackberries. These types are less vigorous than the semi-erect types and produce new canes from root initials (therefore they spread underground like raspberries). There are both thornless and thorny cultivars from this program, some of the most popular are Navaho, Ouachita, Cherokee, Apache, Arapaho and Kiowa.
The University of Arkansas is also responsible for developing the primocane fruiting blackberries. In raspberries, these types are called primocane fruiting, fall fruiting, or everbearing and have been around for some time. Prime-JimTM and Prime-JanTM were released in 2004 and are the first cultivars of primocane fruiting blackberry. They grow much like the other erect cultivars described above, however the canes that emerge in the spring, will flower in mid-summer and fruit in late summer or fall. The fall crop has its highest quality when it ripens in cool climates.
Blackberry production in Mexico has exploded in the past decade. While this industry was initially based on the cultivar 'Brazos' it is now based on 'Tupy'. 'Brazos' was an old erect blackberry cultivar developed in Texas in 1959. 'Tupy' was developed in Brazil and released in the late 1990s. 'Tupy' has the erect blackberry 'Comanche' as one parent, but the other parent is unknown. In order to produce these blackberries in these areas of Mexico where there is no winter chilling to stimulate flower bud development, chemical defoliation and application of growth regulators are used to bring the plants into bloom.
- Black Raspberry, a North American fruit sometimes confused with blackberries.
- Kotata Berry, Oregon State University hybridized.
Standard Cyclopedia of Horticulture
|Standard Cyclopedia of Horticulture|
Blackberry. Cultivated blackberries are the progeny of several species of the genus Rubus. The common garden blackberries are all natives of America, while two little-known but quite distinct forms, the Oregon Evergreen, much grown on the Pacific coast for its fruit and as an ornamental, and the Himalaya, comparatively recently introduced in commercial plantations, come from the Old World. Blackberries are erect-growing perennial plants, bearing black or occasionally whitish fruits which do not separate from the juicy receptacle. Dewberries are distinguished from blackberries only in being procumbent plants, while raspberries differ chiefly in bearing variously colored fruits that fall from a dryish receptacle when ripe. Blackberries are now largely grown only in North America but they are being introduced in gardens in other parts of the world, from some of which, notably in New Zealand, they have escaped and have become troublesome field and roadside plants.
There are many forms of blackberries, species, subspecies and varieties with many hybrids and inter- gradients abounding. At present it is impossible to group the forms with the expectation of a permanent classification. (For a botanical classification see Rubus.) The following is the common arrangement of the horticultural varieties (Bailey): (1) The Long-Cluster varieties are probably best known. These belong to Rubun allegheniensis (Fig. 578). The plants in this group are tall and shrubby with purple canes armed with stout, straight prickles. The fruits are sub-cylindric or thimble- shaped, sweet, dull-colored, with many small closely packed drupelets, and are borne, as the name implies, in long clusters. The White blackberry, having amber- colored fruit and rounder lighter-colored canes, is an albino form of the Long-Cluster blackberry. Taylor and Ancient Briton are the most prominent representatives of the Long-Cluster group, while Iceberg best represents the albino form. (2) Var. sativus furnishes a number of varieties roughly grouped by horticulturists as the Short-Cluster blackberries (Fig. 579). These are characterized by smaller and weaker plants than the preceding, with green and nearly unarmed canes, short, leafless clusters, composed of globose glossy berries of few, large, juicy, irregularly set drupelets. The varieties most commonly grown are Agawam, Kittatinny, Lawton and Snyder. (3) The Leafy-Cluster blackberries belong to a species doubtfully known as R. argutus. Link, and are characterized by low bushy plants bearing short clusters with leaves intermingled with the flowers. Here belong the old Dorchester, one of the first varieties cultivated, and Early Harvest, a valuable commercial sort. (4) The Loose-Cluster blackberries are probably hybrids (Fig. 580) between the first group named and the dewberry (R. villosus, Ait.). The plants are low and spreading, with broad, jagged notched leaves, short clusters of large, roundish berries with juicy, glossy, loosely set drupelets. Early Wilson and Wilson Junior are the best known varieties of this group. (5) The Sand blackberry (R. cuneifolius, Pursh) is the parent of a few unimportant sorts, of which Topsy or the Tree blackberry is the best known. The plants of this group are low and shrubby, with stout recurved prickles; the clusters bear from one to four roundish berries of loosely set drupelets (Fig. 581). (6) The Evergreen blackberries, of unknown origin, to which the Himalaya is closely related, are commonly put in R. laciniatus, Willd., but may be but a cut-leaved form of the European bramble (R. fruticosus, Linn.). The vines are clinging, the foliage evergreen or nearly so, and the berries in the Pacific coast climate are large, black, sweet, and ripen through a period of two or three months. The Oregon Evergreen is the typical variety.
In nature the blackberry propagates itself from suckers and under cultivation young plants from suckers are thriftiest, but many varieties produce but few suckers and the natural process is a slow one with all kinds. A more expeditious method is to use root-cuttings. Such cuttings are usually made during the dormant season by taking up old plants and cutting the roots with pruning-shears into parts 2 inches long. The cuttings are then started under glass, or sown in furrows in well-prepared nursery beds in the spring. The cuttings should fall in sowing 2 inches apart in furrows 3 inches deep and should be covered with well-pulverized soil. The soil must be such that it does not bake as the young shoots appear. It sometimes requires two summers to produce plants ready for setting, but in the South, the Pacific coast, and under favorable circumstances in the East, yearling plants are strong enough for setting. Cuttings should be made from the roots of thrifty, healthy plants, preferably from a young plantation. It is contended and there are many facts to substantiate it, that propagating successive generations of blackberries from root-cuttings results in unproductive or even sterile plants.
Some blackberries from the several varietal groups may be grown in almost every condition of climate and soil in temperate regions, yet this fruit does best in a carefully selected environment. Blackberries cannot stand, without protection, more winter cold than the peach. In dry, hot climates the plants suffer and the berries are few, small, poorly colored and lacking in flavor. A deep, mellow, clay loam, well filled with humus, is most suitable for this fruit. Gravelly and sandy lands are usually too hot and dry. Flat wet lands are quite unsuited and in such soils the plants suffer alike from cold and heat; whatever else may be said of the soil, good drainage is imperative. A northern exposure is usually desirable. Fertilizers are little needed if the land be rich enough naturally to grow fair farm crops. Stable manure often induces rank-growing canes which produce but little fruit. Cover-crops of vetch or clover and some grain as oats or barley, sown in August, will supply much-needed humus and about all the plant- food usually necessary to add.
The plants are set in rows, 7, 8, or 9 feet apart, depending on the soil and the variety, and from 3 to 4 feet apart in the row. There should be room between the rows for a two-horse harrow or cultivator to keep the plantation in good condition. Planting may be done by spade or in furrows 6 or 7 inches deep. A hoed- crop is usually grown between the rows the first year but seldom the second, as the plants need all the food and moisture to make sufficiently strong plants to bear a crop the third season. The canes are allowed to grow the first year to a height of 18 to 30 inches, when they should be cut back a few inches. The plants are thus pruned to cause them to crow low, stocky and upright, with many lateral branches, and so avoid the necessity of a trellis and yet be able to hold the crop up well. Trellising is troublesome and expensive.
Subsequent training and pruning consist in keeping the plants well branched, low and stocky, and in regulating the amount of bearing wood. Success in growing blackberries depends largely upon proper training and pruning. The fruit is borne upon one-year-old canes which should be removed as soon as the crop has been harvested. To allow them to stand through the growing season jeopardizes the proper development of the new canes, and often exposes them to infection from fungi. Five or six canes to the plant are quite enough; if there are more, the size and quality of the crop will be reduced. The canes should be headed-in annually during the growing season, as recommended for the first year. In the spring laterals are shortened- in, the amount of cutting - back depending upon how close the fruit is borne to the cane on the variety in hand. The laterals are usually left from 12 to 20 inches long. This spring pruning may be and often should be made a thinning process. Managed according to the directions just given, the plants need neither stakes nor trellises. In some plantations, however, a wire is stretched along each side of the row to hold the plants up, and in others, notably along the Hudson River, the plants are trained on two-wire trellises. In northern climates the training must be such as to provide for winter protection for many varieties. Winter protection consists in laying down the canes and covering them wholly or in part with a thin mulch of straw or earth. The method of laying down must be varied with the variety, the soil and the amount of protection to be given. Three men can do the work most expeditiously; one goes ahead and digs the earth from the front and back of the roots, a second with fork or foot pushes the plant forward to the ground, the third puts on the mulch of earth or straw. Tender varieties are wholly covered, but the hardier sorts need only a covering on the tips of the canes. The plants are raised in the spring just before or as the buds begin to burst. Care must be taken not to break or split the canes. Such protection at present prices of labor will cost from eight to twelve dollars per acre. Winter injury is sometimes a matter of moisture as well as of temperature, and, in irrigated regions, late irrigation may obviate the necessity of a winter covering.
Thorough cultivation is essential for the proper conservation of moisture in a blackberry plantation, abundant moisture being a prime requisite for this fruit. It must be frequent and constant until the berries begin to turn in color. After the crop is harvested, the cultivator should be used to put the ground in shape for the cover-crop. The cultivator must be shallow- cutting since deep cultivation injures the roots, thereby weakening the plants, and inducing suckering. Mulching to take the place of cultivation is not to be recommended, except in small patches, and in the row with cultivation between rows.
Blackberries should not be harvested until fully ripe, and the sooner eaten after picking the better the quality. The fruits are not ripe when they attain full color but must be left on the bushes until soft, at which time they should part from the stem readily when the cluster is shaken. In picking, the berries should not be exposed to the sun. Well treated, the plante should bear some fruit the second season, and the third summer should give a fair crop. The length of time the plants will bear depends upon the variety, the soil and the treatment. When the stools become thin, the canes weak and the fruits small, the plantation should be cut down, this time coming usually when the bushes are ten or twelve years old.
Blackberry-growers have several troubles to contend with. Late frosts occasionally do much harm in northern latitudes. Borers often do much damage to canes and can be circumvented only by cutting out infested stalks. Two fungous diseases, orange rust and anthrac-nose, are dangerous, and are successfully kept in check only by cutting out the diseased wood. Root-galls are often found but it is doubtful whether they do much damage, and it is certainly not worth while trying to control them. Good treatment, especially as regards cultivation and pruning, with careful attention to destroying the pests mentioned as soon as practicable, will keep the plants in health.
The yields and profits in blackberry-growing are most encouraging to small- fruit - growers. In a plantation well cared for, a crop of two hundred bushels per acre may be expected. Blackberries are not suitable for long-distance shipments and monetary rewards come from local markets and here they are often large when climate; soil and general conditions are favorable.
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963