Make the best of blackcurrants

Press, 24 June 1983, Page 12

Make the best of blackcurrants

GARDENING

M.Lusty

Black currants have become an increasingly popular berry fruit in the last few years, possibly because of the greater awareness and publicity given to their very high vitamin C content. The fruit has countless uses, whether consumed in a fresh state, or stewed, bottled, made into jam, jelly, or as blackcurrant juice. The plant is relatively easy to grow, is fairly adaptable, does not pose any major management problems and can produce a surprisingly heavy yield of fruit. Most fruits and vegetables are grown in the limited areas usually devoted to these commodities in present-day gardens, so the objective should be to get the best possible return from them. Site is all important. It is not at all uncommon to find that blackcurrant bushes have been or rather crammed into one of the poorest parts of the * garden. Although tolerant of shade and cold, as well as far wetter conditions than most other generally grown fruits and vegetables, blackcurrants are susceptible to frost damage when in bud. They are also averse to exposure to strong (cold) winds.

They respond to a position in a full sun and a good moisture retentive soil,

which has been supplemented with organic matter.

Shelter will not only provide the necessary protection from wind which can cause running off — the dropping of young fruit — but also reduce effects from very hot conditions which also can reduce the crop, particularly where little watering is done. Plants may be offerd for sale as one, two, and even three-year-old, bushes. Older plants will have the advantage of having been pruned hard back at least once, which should have promoted more growth

from the basal region so that it does not emanate from a leg. One-year-old bushes should have all shoots cut right back to within two to three buds of the base at planting time. Plants should be set into the soil to the base of the lowest off-shot. Where more than one plant is put in a minimum spacing of 1.25 m between them is advocated.

Blackcurrants respond to fertile, only slightly acid, moisture retentive soils, and any improvements made in these directions will be subsequently well rewarded. The shallow rooting

nature of these plants also means that cultivation in their vicinity should be minimal and not deep. Initial removal of all perennial weeds, and mulching during the season will help to restrict such unwanted growth. It will also help to conserve moisture, and at the same time keep the roots cool. Compost or old straw are most suitable for this purpose. Blackcurrants are also most responsive to the availability of nutrients in the soil especially nitrogen and to a lesser degree potassium.

A suggested fertilier mixture comprising 3 parts ammonium sulphate, 2/superphosphate and %/potassium sulphate (or nitrate), all by weight, to a maximum of Ikg for a fully established bush should be applied in late August. Alternatively, one of the proprietary berry fruit mixtures can be given. The application should be evenly spread around the plant to the extremity of its branch drip line, and not dumped into the middle of it. There have not been many varieties to choose from, but although most of them have been with us for

a long time now they have generally proved to be good; they include Cotswold Cross, Daniel’s Late September, and Goliath.

More recently Magnus has become prominent, and one or two other varieties are also being offered by the trade.

Cotswold Cross is the earliest to ripen its fruit, though somewhat unevenly so, from about mid-Decem-ber. Both Goliath and Magnus are later, Daniel’s Late September being later still but all are very much more even in this respect as well as being more upright in growth habit. Although diseases do not seem to be a problem, some pests can cause a considerable amount of both damage and debility.

The most common trouble is bud loss and brittle stem caused by the larvae of the currant clear wing moth. Unfortunately, there is at present no good method of controlling this pest which seems to be becoming more prevalent although experiments using a specific nematode have been shown to be most encouraging so far.

One way to reduce the pest in the home garden is make sure that all prunings are gathered up and burned. Aphids, mites, and scale are common enough to cause concern, but all can be effectively controlled before they create set-backs. Acephate, tedrifon, and spraying oil, respectively, are suitable controls.

Fruit is borne on shoots produced in the previous season and also on spurs on older wood. Annual pruning should consist of encouraging strong well spaced basal development by cutting out as much of the old wood as feasible. Remaining shoots should not be tipped.