St John’s-wort (Hypericum perforatum) is one of the oldest and most well-known medicinal species, being widespread in the spontaneous flora of many countries of the world. It is widely used in folk medicine.

It can be frequently found in Europe, Central Asia, North America, Australia and Northern Africa.

Botanical characteristics

Hypericum perforatum is a perennial, herbaceous species.

The underground part is represented by a short rhizome, from which grow many roots and several stems.

The stem is up to 100 cm high, up to 3-5 cm thick, glabrous, cylindrical, usually with two longitudinal edges often lignified on the topside. It develops short sterile branches in the leaves axils. On the surface of the stem, especially on the edges, elongated black spots can be seen.

The leaves, oppositely arranged, sessile, elliptical, or linearly ovate, on the main stems are up to 3.5 cm long, and the sterile branches are partly glabrous and display many translucent spots (hence the name perforatum), as well as elongated black spots.

The flowers are arranged in corymbs, at the top of the main stem and branches, being made up of 5 lanceolate sepals, 1-2 mm wide, and of 5 golden-yellow petals, 10-13 mm long, up to 8 mm wide, on one side with an entire margin, and on the other side with the margin usually serrated and with black spots. The stamens are numerous, shorter than the petals, arranged in 3 bundles; the gynoecium is bicarpellate, superior, with 3 styles.

The fruit is an oval capsule, 2 times longer than the calyx, divided into 3 chambers.

The seeds are cylindrical, about 1 mm long, 0.4 mm thick, colored in dark brown. It blooms from June to September.

Species, varieties. In the spontaneous flora, the following species are the most common: H elegans Stephan, H. maculatum Cr, H. hirsutum L., H. tetrapterum Moench., H. montanum L.

Environmental requirements

St John’s-wort is a species with great ecological plasticity, which does not have special requirements in terms of climatic factors.
The seeds germinate at 5-6° C, the optimum temperature being 20° C. The seedlings are fragile and grow slowly in the first year of vegetative growth and do not bear fruit until the second year. St John’s-wort becomes resistant to unfavorable environmental conditions in the second year of vegetative growth.

Light. St John’s-wort is a light-loving species that cannot tolerate shaded areas. The light contributes to volatile oil accumulation and the species reacts favorably to strong light. As a result, the southern areas are more favorable for the cultivation of St John’s-wort, in terms of quality.

Temperature. The species resists well to low temperatures as well as high temperatures; the latter favorably influences the accumulation of volatile oil.

Water. Due to the well-developed root system, St John’s-wort has good resistance to summer drought. However, it reacts favorably to areas with rich precipitations.

Soil. It grows relatively well in all types of soil, regardless of pH, provided that they are not strongly compacted. Heavy soils and those with excessive moisture are not recommended. St John’s-wort reacts favorably to the natural fertility of the soil.

Cultivation

The plant’s place in the crop rotation. Being a perennial species, St John’s-wort is not included in the crop rotation with annual species. Although it does not display any special requirements regarding the preceding plant, the best results are obtained if it is cultivated after species that are harvested in summer and leave the land free of weeds.

The most suitable preceding plant is corn, and cereals, sown in soils with a low degree of weeding and fertilization. St John’s-wort should return to the same place after 4-5 years.

Fertilizing. In order to ensure the necessary nutrients, the regular administration of fertilizers specially formulated for this purpose is recommended.

Preparing the soil

After harvesting the preceding plant, the soil must be plowed to a depth of 22-30 cm, then tilled 1-2 times with a disc, keeping the soil clean and loose until sowing.

If the soil is dry after harvesting the preceding plant, disking is carried out and also plowing after the first rain.

The preparation of the seedbed is done before sowing, by leveling, thorough shredding and then compacting the soil, using for this purpose the combiner followed by the roller.

Propagation. St John’s-wort is propagated through seeds sown directly in the field.

Sowing season

It is sown in winter, and in wetlands also in spring. .

Sown in early winter, the plants sprout 2-3 weeks earlier than the spring-sown ones, grow vigorously, achieve an optimal crop density, ensuring high yields. For sowing in spring, the seeds must be layered in the sand for 2-3 months, being exposed to cold during this period. Before sowing, the seeds have to be dried out.

Distance and depth of sowing. St John’s-wort should be sown at a distance of 50 cm between rows. In these conditions, the care works can be carried out mechanically. The sowing depth has to be 0.3-0.5 cm.

Seed norm. This is 3-4 kg/ha, depending on the quality indicators of the seed and the degree of soil preparation.

Care

Immediately after sprouting, the plants are fragile and grow slowly in the first year of vegetative growth. It is, therefore, necessary to carry out maintenance work even before the plants emerge, by weeding each row 3-4 times in the first year of growth.

In the second and subsequent years, it is recommended to remove the dried stems before the crop starts growing. During the summer, every year 2-3 hoeings are carried out, these being mandatory also after each harvest. Before harvesting, the weeds must be removed from the crop.

Diseases and pests

In some years, characterized by favorable conditions for disease development, is reported the attack of Fusarium and Verticillium fungi, which can even lead to crop failure. Plants in the third year of growth are more susceptible. No pests specific to St John’s-wort crops have been reported so far.

Harvesting

Harvesting season. When establishing the optimal harvest time, the quantity of the raw vegetable material produced at a given time must be taken into account, as well as the content in active principles accumulated in the plant.

St John’s-wort has to be harvested on clear and warm days, in the hours with maximum sunshine.

A second harvest can be obtained in autumn after regeneration of the plants harvested in summer, 30-40 days after the first harvest.

Harvesting method. Depending on the size of the cultivated area, St John’s-wort can be harvested with a sickle, with a scythe or with a mechanical mower to which the cutting mass will be adjusted, so that the grass is cut to a height of 20-25 cm, to avoid harvesting the lignified part of the stem.  

It is recommended to harvest the tips of leaves, flowers and flower buds to a length of up to 30 cm or the entire herb with the mower.

In order to obtain the seeds, St John’s-wort has to be harvested when the seeds are brown. This is done also with the mower, the cut mass being adjusted higher. The harvested plants must be laid to dry and then threshed.

The obtained seeds are conditioned, achieving a production of 100-140 kg/ha.

Processing the raw material

Drying. Naturally, drying should be done in clean and airy rooms, the plants being placed in a thin layer, to dry quickly, without changing their color or appearance.

In the dryer, it is recommended to dry the plants at low temperatures, of 35° C, in order not to destroy the active principles.

Packing, storage. The dried plants have to be carefully gathered so as not to shake the leaves and flowers and must be packed in cloth bags. They must be kept in dry and clean rooms. St John’s-wort has a characteristic aroma and a bitter, astringent taste.