How to Grow Blackberries
Every autumn the remaining hedgerows in the countryside are studded with family groups busily engaged in picking wild blackberries. A large proportion of the fruit is devoured on the spot and the rest is whisked home for stewing with apples; freezing or making into jam or jelly. Such is the popularity of our native fruit. But all ardent blackberryers will testify that what with hedgerow clearances, the relentless advance of the urban sprawl and losses due to careless stubble burning—to say nothing of drought—one has to travel much further now to fill baskets than used to be the case. The answer is to grow blackberries in the garden. The blackberry is very accommodating and tolerant of adverse site andconditions, and can therefore be used to turn the rough corners of the garden, if any there be, to profit. An excellent crop has been gathered each year in one large and somewhat neglected garden from a wire fence used once to confine chickens, and that with no attention whatsoever beyond picking and the minimum of pruning to keep the rods within reasonable bounds. The cultivated varieties tend to lack the sharpness and bite of their wild cousins but are well worth the space and effort required.
Soil and site
Although the blackberry will grow and crop on poor soil and in shady positions, it will only give of its bountiful best if offered well prepared soil, plenty of summer moisture and an open site. In other words, the recommendations for soil, site and manuring made earlier for the raspberry will suit the blackberry splendidly, but if really necessary it will still crop satisfactorily where the raspberry would be a dismal failure.
We all know how the blackberry is propagated in the wild because it is obvious that those big clumps extend outwards partly by new, but even more by a process of natural . This is accomplished as the young canes arch over under their own weight, causing the tips to come into contact with the ground. These tips become covered with debris, which allows them to root and at the same time to produce another aerial rod which stretches outwards to new territory in a series of arching loops.
If the gardener wishes to increase his stock all he has to do is to copy nature. The tip of a selected young cane is buried shallowly in July or thereabouts, securing the parent cane to ensure that the tip is properly anchored. It helps if a couple of handfuls of used pottingare placed around the buried tip, and rooting is accelerated if the tip is kept moist. During the next winter or spring the new emergent rooted shoot can be detached, lifted and planted to carry on an independent existence.
Blackberries can also be readily propagated on a large scale by single bud, but that technique calls for special facilities and need not concern the average gardener.
Spread out the roots of the new plant—home raised or purchased—so that they occupy as large a feeding zone as possible, the soil firmed and the surface mulched in accordance with basic good practice and principles. Each newly planted blackberry must then be shortened back to about 30cm (1ft). The plants should be given plenty of room. The very vigorous varieties, such as Himalaya Giant, will need about 4.5m (15ft) while the more refined types such as the Parsley-leafed will manage with 3m (10ft).
Training and pruning
The gardener, like the modern parent of young children, has the choice of allowing the canes to scramble around in a free-for-all fashion, or to adopt the stern alternative of insisting on a bit of discipline. There are situations where nature can be left to herself, more or less, but the best results are beyond all doubt obtained from formal training. One system, which gives excellent results, allows the fruiting rods to be kept separate from the rampant young cane, which makes for an easier life for the owner. It also enables a greater length of fruiting cane to be utilized because of the manner in which the rods are trained in a weaving and looping pattern on the bottom three wires. This operation calls for thick gloves and old clothes, combined with calm weather and a mild winter’s day. The young cane is tied in as it develops during the summer, guided into the central V-shaped space and then along the top wire. After fruiting, the old rods are cut out and the new cane tied in on the bottom wires.
If the prospect of battling with the thorny canes any more than absolutely necessary proves daunting, the one-way training system has much to commend it. Here, after the young cane is tied into its fruiting quarters, no further handling is required. Obviously this system does not use the space as effectively as the first one.
The pruning of blackberries has, in a way, already been implied from the descriptions of training. Most varieties have biennial stems, which die after fruiting and are then replaced by the young canes, but the fruiting rods of some of the more vigorous varieties are perennial. It is useful to know this, because if there are not enough young canes produced in a particular year the old rods can be retained for another season. All that is necessary, apart from any repositioning required, is to prune the laterals which carried the fruits back to 2.5cm (1in).
In its growth habit the blackberry resembles a rambling rose, which suggests that it could be trained vertically.
A walk in the country in spring quickly reveals that even the wild blackberry comes from a very mixed family. Botanically, the blackberry is Rubus fruticosus, but the type has mutated into a number of sub-species, including the nicely named Rubus laciniatus, the cut-leafed or-leafed species. Some authorities suggest that the very vigorous Himalaya Giant comes from Rubus procerus. Additionally, new scientific breeding has produced new varieties to add to the range. With this background it is not surprising that there is a wide choice available. The commercial producers grow the vigorous varieties because they crop most heavily, so if you have the space it makes some sense to grow Himalaya Giant, Bedford Giant or John Innes. All those mentioned will freeze satisfactorily. Be warned, however, that vigorous really does mean vigorous, and they are heavily armed with thorns. More manageable, because it is relatively dainty, is the parsley-leafed variety. There is a thornless clone, which is understandably popular. All in all the variety most amateurs will be happiest with is the one offered as Oregon Thornless.
Pests and diseases
Always plant healthy looking plants, never start with weak, sickly canes, and particularly so if the stem is scarred and cankered.
Having made a good start with healthy plants in well-prepared soil in a good site there is not much to go wrong, save for the troubles which come in from your neighbours’ gardens and against which it is sensible to take at least minimum precautions. A spray of malathion (or rogor) should be applied as soon as aphids are seen, taking care to observe the manufacturer’s instructions. The raspberry beetle is best controlled by a derris spray applied in the late evening as the first flowers open.
Ifare kept at bay and the plants are properly nourished they should last in a heavy cropping state indefinitely and provide a pleasant investment.