This section is from the book "The Standard Cyclopedia Of Horticulture Vol2", by L. H. Bailey. See also: Western Garden Book: More than 8,000 Plants - The Right Plants for Your Climate - Tips from Western Garden Experts.
The usual method of propagating currants is by means of cuttings. These root very readily and good plants are secured after one season's growth. The best time to make the cuttings is in the autumn, as currants begin to grow very early in the spring, and once the buds have swollen they cannot be rooted successfully. Wood of the current season's growth is used. This may be cut early in the autumn as soon as the wood has ripened, from the end of August to the middle of September being the usual time. It should be cut in as long pieces as possible to save time in the field, and put in a cool moist cellar or buried in sand. If the cuttings can be made at once, it is best to do so. These are made by cutting the wood into pieces, each about 8 to 10 inches long, although an inch or two more or less is not of much consequence. The base of the cutting should be made with a square cut just below the last bud. There should be at least 1/2i inch of wood left above the top bud of each cutting, as there should be a strong growth from the upper bud, and if the wood is cut too close it is liable to be weakened. A sloping cut is best for the upper cut, as it will shed rain better, but this is not important.
When made, the cuttings should be planted at once, which is usually the best plan, or heeled in. If heeled in, they should be tied in bundles and buried upside down in warm well-drained soil, with about 3 inches of soil over them. The object of burying them upside down is that by this method the bases of the cuttings will be nearer the surface where the soil is warmer and there is more air, and will callus more quickly than if they were further down. The cuttings should callus well in a few weeks, and may then be planted outside, if thought advisable. Cuttings may be kept in good condition over winter by heeling-in or burying in sand in a cool cellar, or after callusing under a few inches of soil outside, they may be left there over winter if covered with about 4 to 5 more inches of soil to prevent their drying out. Good results are secured with the least trouble by planting the cuttings in nursery rows as soon as they are made. The soil should be well prepared and should be selected where water will not lie. Furrows are opened 3 feet apart and deep enough so that the top bud, or at most two buds, will be above ground. The cuttings are placed about 6 inches apart on the straight side of the furrows and soil thrown in and tramped well about them.
When only a smaller number are to be planted a trench may be opened with a spade. It is important to have a large proportion of the cutting below ground, as more roots will be made and the plants will be stronger. There would also be danger of the cuttings drying up before rooting if too much of the wood is exposed. If the season is favorable the cuttings should callus well and even throw out a few roots by winter. Where there is little snow in winter, it is a good practice to cover the tops of the cuttings with about 2 inches of soil, which will be a good protection for them. This soil should be raked off in spring. In the spring, cultivation should be begun early and kept up regularly during the summer to conserve moisture and favor rooting and the development of the bushes. By autumn they should be large enough to transplant to the field.
Fig. 1151. Common currant-Ribes vulgare, in bloom. (X 2/3)
In Great Britain and Europe, currants are often grown in tree form and are prevented from throwing up shoots from below ground by removing all the buds of the cuttings except the top one before planting in the nursery. This system is not recommended for most parts of America as it has been found by experience that snow breaks down currants grown in this way, and when borers are troublesome it is not wise to depend on one main stem.
Most of the cultivated varieties of currants have originated as natural seedlings, little artificial crossing having been done with this fruit. Currants grow readily from seeds, and it is easy to get new varieties in this way. The seeds are washed out of the ripe fruit, and after drying, may either be sown at once or mixed with sand and kept over winter in a cool dry place and sown very early in the spring. The best plan is to sow them in the autumn in mellow well-prepared and well-drained soil, since when this is done they will germinate very early in the spring, while if sown in the spring the seed may be all summer without sprouting. The seed should not be sown deep, from 1/4 to 1/2 an inch being quite sufficient. If sown very deep they will not germinate. The young plants may be transplanted from the seed-bed to the open in the autumn of the first year if large enough, but if the plants are very small they may then grow another season, when they should be planted out at least 4 by 5 feet apart, so as to give them room enough to fruit for several seasons, in order that their relative merits may be learned. If intended to remain permanently, the plants should be at least 6 by 5 feet apart. The bushes should begin to bear fruit the second or third year after planting out.
Each bush will be a new variety, as cultivated fruits do not come true from seed. If a seedling is considered promising it may be propagated or increased by cuttings, as already described.
Currants should be planted in rich soil in order to get the best results. The soil should also be cool, as the currant is a moisture-loving bush. The currant roots near the surface; hence if the soil is hot and dry the crop will suffer. A rich, well-drained clay loam is the best for currants, although they do well in most soils. If the soil is not good, it should receive a good dressing of manure before planting, which should be well worked into the soil, the latter being thoroughly pulverized before planting is done. A northern exposure is to be preferred, as in such a situation the currants are not likely to suffer in a dry time.
The best time to plant currants is in the autumn. If planted in the spring, they will probably have sprouted somewhat before planting, and on this account their growth the first season will be checked. When the soil is in good condition, currants, especially the black varieties, make strong growth, and the bushes reach a large size; hence it is best to give them plenty of space, as they will do better and are more easily picked than if crowded. Six by 5 feet is a good distance to plant. If planted closer, especially in good soil, the bushes become very crowded before it is time to renew the plantation. Strong one-year-old plants are the best, but two-year-old plants are better than poorly rooted yearlings. It is better to err on the side of planting a little deeper than is necessary than to plant too shallow. A good rule to follow is to set the plants at least an inch deeper than they were in the nursery. The soil should be well tramped about the young plant so that there will be no danger of its drying out.
After planting, the soil should be leveled and the surface loosened to help retain moisture.
As the currant, to do well, must have a good supply of moisture, cultivation should be begun soon after planting, and the surface soil kept loose during the summer. While the plants are young the cultivation may be fairly deep between the rows, but when the roots begin to extend across the rows, cultivation should be shallow, as many of the roots are quite near the surface.
After the first application of manure, no more should be necessary until the plants begin to fruit, unless other crops are grown between, after which an annual top-dressing of well-rotted barnyard manure is desirable. When only a light application of manure is given, the addition of 200 to 300 pounds to the acre of muriate of potash would be very beneficial. Wood-ashes also would make a good fertilizer with barnyard manure. There is little danger of giving the currant plantation too much fertilizer. Unfortunately, it is usually the other way, this fruit being often very much neglected.