--Cultivation--- ...In connexion with specimens of the wild plant, it is most difficult to trace the conditions which determine the variations, but it has been ascertained that a light, permeable and chalky soil is the most suitable for this crop. This, joined to a south-west aspect on the slope of a hill, gives specially good results as regards a high percentage of alkaloids. The limits of growth of Belladonna are between 50 degrees and 55 degrees N. Lat. and an altitude of 300 to 600 feet, though it may descend to sealevel where the soil is calcareous, especially where the drainage is good and the necessary amount of shade is found. The question of suitability of soil is especially important. Although the cultivated plant contains less alkaloid than that which grows wild, this in reality is only true of plants transported to a soil unsuited to them. It has been found, on the contrary, that artificial aids, such as the judicious selection of manure, the cleansing and preparation of the soil, destruction of weeds, etc., in accordance with the latest scientific practice, have improved the plants in every respect, not only in bulk, but even in percentage weight of alkaloidal contents.
Authorities differ on the question of manuring. Some English growers manure little if the plants are strong, but if the soil is really poor, or the plants are weak, the crop may be appreciably increased by the use of farmyard manure, or a mixture of nitrate of soda, basic slag and kainit. Excellent results have been obtained in experiments, by treating with basic slag, a soil already slightly manured and naturally suited to the plant, the percentage of total alkaloid in dry leaf and stem from third-year plants amounting to 0.84. In this case, the season was, however, an exceptionally favourable one, and, moreover, the soil being naturally suited to the plant, the percentage of alkaloid obtained without added fertilizer was already high. Speaking from the writer's own experience, Belladonna grows in her garden at Chalfont St. Peter. The soil is gravelly even stony in some parts, with a chalk subsoil - the conditions similar to those that the plant enjoys in its wild state. This neighbourhood, in her opinion, is a suitable one for growing fields of Belladonna as crops for medicinal purposes.
Notes and statistics taken from season to season, extending over nine years, have shown that atmospheric conditions have a marked influence on the alkaloidal contents of Belladonna, the highest percentage of alkaloid being yielded in plants grown in sunny and dry seasons. The highest percentage of alkaloid, viz. 0.68 per cent, was obtained from the Belladonna crop of 1912, a year in which the months May and June were unusually dry and sunny; the lowest, just half, 0.34 was obtained on the same ground in 1907, when the period May and June was particularly lacking in sunshine. In 1905, August and September proving a very wet season, specimens analysed showed the low percentages of 0.38 and 0.35, whereas in July and October, 1906, the intervening period being very fine and dry, specimens analysed in those months showed a percentage of 0.54 and 0.64 respectively.
There appears to be no marked variation in alkaloidal contents due to different stages of growth from June to September, except when the plant begins to fade, when there is rapid loss, hence the leaves may be gathered any time from June until the fading of the leaves and shoots set in.
In sowing Belladonna seed, 2 to 3 lb. should be reckoned to the acre. Autumn sown seeds do not always germinate, it is therefore more satisfactory to sow in boxes in a cool house, or frame, in early March, soaking the soil in the seed-boxes first, with boiling water, or baking it in an oven, to destroy the embryo of a small snail which is apt, as well as slugs and various insects, to attack the seedlings later. Pieces of chalk or lime can be placed among the drainage rubble at the bottom of the boxes. Belladonna seed is very slow in germinating, taking four to six weeks, or even longer, and as a rule not more than 70 per cent can be relied on to germinate. On account of the seeds being so prone to attack by insect pests, if sown in the open, the seed-beds should first be prepared carefully. First of all, rubbish should be burnt on the ground, the soil earthed up and fired all over, all sorts of burnt vegetable rubbish being worked in. Then thoroughly stir up the ground and leave it rough for a few days so that air and sun permeate it well. Then level and rake the bed fine and finally give it a thorough drenching with boiling water. Let it stand till dry and friable, add sharp grit sand on the surface, rake fine again and then sow the seed very thinly.
Considerable moisture is needed during germination. The seedlings should be ready for planting out in May, when there is no longer any fear of frost. They will then be about 1 1/2 inch high. Put them in after rain, or if the weather be dry, the ground should be well watered first, the seedlings puddled in and shaded from the sun with inverted flower-pots for several days. About 5,000 plants will be needed to the acre. If they are to remain where first planted, they may be planted 18 inches apart. A reserve of plants should be grown to fill in gaps.
The seedlings are liable to injury by late frosts and a light top dressing of farmyard manure or leaf-mould serves to preserve young shoots from injury during sudden and dangerous changes of temperature. They do best in shade. In America, difficulties in the cultivation of Belladonna have been overcome by interspersing plants with rows of scarlet runners, which, shading the herb, cause it to grow rapidly. Healthy young plants soon become re-established when transplanted, but require watering in dry weather. Great care must be taken to keep the crop clean from weeds and handpicking is to be recommended.
By September, the single stem will be 1 1/2 to 2 1/2 feet high. A gathering of leaves may then be made, if the plants are strong; 'leaves' include the broken-off tops of the plants, but the coarser stems are left on the plant and all discoloured portions rejected, and the plants should not be entirely denuded of leaves.
Before the approach of winter, plants must be thinned to 2 1/2 to 3 feet apart, or overcrowding will result in the second year, in which the plant will bear one or two strong stems.
The writer finds that the green tips and cuttings from side branches root well and easily in early summer, and that buds with a piece of the root attached can be taken off the bigger roots in April, this being a very successful way of rapid propagation to get big, strong plants.
In the second year, in June, the crop is cut a few inches above the ground, while flowering, and delivered to the wholesale buyer the same day it is cut.
The average crop of fresh herb in the second and third years is 5 to 6 tons per acre, and 5 tons of fresh leaves and tops yield 1 ton of dried herb. A second crop is obtained in September in good seasons.
The yield per acre in the first year of growth should average about 6 cwt. of dry leaves.
The greatest loss of plants is in wet winters. Young seedling plants unless protected by dead leaves during the winter often perish. On the lighter soils there is less danger from winter loss, but the plants are more liable to damage from drought in summer.
One of the principal insect pests that attack Belladonna leaves is the so-called 'fleabeetle.' It perforates the leaves to such an extent as to make them unfit for sale in a dried state. It is when the plants are exposed to too much sunlight in open spots that the attacks of the beetle are worst, its natural habitat being well-drained slopes, partly under trees. If therefore the ground around the plants is covered with a thick mulch of leaves, they are not so likely to be attacked. The caterpillars from which the beetles come feed on the ground, and as they dislike moisture, the damp leaves keep them away. If napthalene is scattered on the soil, the vapour will probably help to keep the beetles off. The only way to catch them is to spread greased sheets of paper below the plants, and whenever the plants are disturbed a number of beetles will jump off like fleas and be caught on the papers. This at best only lessens the total quantity, however, and the other methods of precaution are the best.
The plant is dug or ploughed up during the autumn in the fourth year and the root collected, washed and dried, 3 to 4 tons of fresh root yielding a little over 1 ton of dry root. In time of great scarcity, it would probably pay to dig the root in the third year.
Old roots must be replaced by a planting of young ones or offsets, and if wireworm is observed, soot should be dug in with replacements.
Although Belladonna is not a plant that can be successfully grown in every small garden, yet in a chalky garden a few plants might be grown in a shady corner for the sake of the seed, for which there is a demand for propagation. Those, also, who know the haunts of the plant in its wild state might profitably collect the ripe berries, which should then be put into thin cotton bags and the juice squeezed out in running water. When the water is no longer stained, wring the bag well and turn out the seeds on to blotting paper and dry in the sun, or in a warm room near a stove. Sieve them finally, when dry, to remove all portions of the berry skin, etc.
Belladonna has been successfully cultivated in the neighbourhood of Leningrad since 1914, and already good crops have been obtained, the richness of the stems in alkaloids being noteworthy. It is stated that in consequence of the success that has attended the cultivation of Belladonna in Russia, it will no longer be needful to employ German drugs in the preparation of certain alkaloids. Much is also being collected wild in the Caucasus and in the Crimea.
It is hoped that if sufficient stocks can be raised in Britain, not only will it be unnecessary to import Belladonna, but that it may be possible to export it to those of our Dominions where the climate and local conditions prevent its successful culture, though at present it is still included among the medicinal plants of which the exportation is forbidden.
The following note on the growth and cultivation of Belladonna is from the Chemist and Druggist, of February 26, 1921:
'Belladonna is a perennial, but for horticultural purposes it is treated as a biennial, or triennial plant. The root in 3 years has attained very large dimensions around Edinburgh; in fact, often so large as to make the lifting a very heavy, and therefore costly, matter, and in consequence 2 years' growth is quite sufficient. One-year-old roots are just as active as the three-year-old stocks, and to the grower it is merely a matter of expediency which crop he chooses to dig up. The aerial growth is very heavy, twoyear-old plants making 5 to 6 feet in the season if not cut for first crop, and if cut in July they make a second growth of 2 to 3 feet by September. To obtain a supply of seeds certain plantations must be left uncut, so as to get a crop of seeds for the next season. Moisture is, from a practical point of view, a very important matter. A sample, apparently dry to the touch, but not crisp, may have 15 per cent to 20 per cent of moisture present. Therefore if a pharmacist was to use a sample of such Belladonna leaves, although assayed to contain 0.03 per cent of alkaloids, he would produce a weaker tincture than if he had used leaves with, say, only 5 per cent of water present. The alkaloidal factor of this drug is the index to its value. Both the British and the United States Pharmacopoeias adopt the same standard of alkaloidal value for the leaves, but the British Pharmacopceia does not require a standard for the root, which is one of those subtle conundrums which this quaint book frequently presents! Plants grown in a hard climate, such as Scotland, give a good alkaloidal figure, which compares favourably with any others. For roots, the British Pharmacopoeia as just stated, requires no standard, but United States Pharmacopceia standard is 0.45 per cent, and Scottish roots yielded 0.78 per cent and 0.72 per cent. There is not a great deal of alkaloidal value in the stalks. About 0.08 in the autumn.'
