How to Grow Rosemary? Latest Cultivation Techniques and Methods Tutorial

Rosemary is a valuable natural aromatic plant that gives off a fresh fragrance during the growing season and has the effect of refreshing the mind and invigorating the spirits. Its stems, leaves and flowers have a pleasant scent, and the aromatic oil extracted from the flowers and tender branches can be used to blend raw materials for cosmetics such as air fresheners, perfumes and soaps, giving it extremely high cultivation value. Let us take a look at the cultivation techniques for rosemary below!

Growth Habits of Rosemary

Rosemary originated in Europe and along the Mediterranean coast of North Africa, and is mainly cultivated as an economic crop in southern Europe. It was introduced into China during the Cao Wei period, and is now mainly planted in most parts of the south and in the Shandong region. It likes a warm climate, but grows slowly during the high-temperature period on the flatlands of Taiwan, China; temperatures without cold spells in winter are more suitable for its growth. As for water supply, since the leaves of rosemary are leathery, it is fairly drought-tolerant, so soil rich in sand that drains well is more conducive to its growth and development. It is worth noting that rosemary grows slowly, so its ability to regenerate is not strong.

Propagation Techniques for Rosemary

1. Sowing: Seedlings are generally raised in a greenhouse in early spring, either by traditional soil-based seedling raising or plug-tray seedling raising, but the germination rate is very low, generally only 10-20%, and rosemary grows extremely slowly in the first year. Even by autumn the plant is not much larger than when it was just planted, and it takes 2-3 years to form a large yield, which is very slow. Therefore, vegetative propagation is generally used in production. However, plants grown from seed have a more fragrant scent, so which propagation method to use depends on the need.

2. Cuttings: Rosemary cutting propagation is mostly carried out from winter to early spring. Select fresh, healthy stems that have not yet fully lignified as cuttings, cut them about 10-15 cm from the top, remove about 1/3 of the leaves from the lower part of the branch, and insert them directly into the medium. Keep the medium moist, and roots will form in about 3-4 weeks. After 7 weeks they can be planted out in the open field. The minimum night temperature for cuttings is 13°C.

3. Layering: Rosemary layering propagation mainly makes use of the characteristic that rosemary stems can produce adventitious roots. Bend branches close to the ground down and cover them with soil, leaving the top in the air. Once new roots have grown, cut them from the parent plant to form new individuals and plant them out in the open field.

Cultivation Techniques for Rosemary

1. Land preparation: Before transplanting rosemary, first dig holes in the leveled land according to the plant and row spacing, apply a small amount of base fertilizer, then cover the base fertilizer with a thin layer of soil, and it can be transplanted. Usually the seedlings transplanted in the field are mother seedlings that have survived after cuttings have rooted. The transplanting spacing is 40×40 cm, and the number planted per mu is 4000-4300 plants. In central and southern Yunnan, planting can be done all year round, with spring and autumn being the best.

2. Planting: For planting rosemary, it is best to choose cloudy days, rainy days, or mornings and evenings when the sunlight is not strong. After transplanting, water thoroughly to settle the roots. When watering, do not let the seedlings topple over; if any fall over, straighten and firm them promptly. Water rosemary a second time 5 days after planting (depending on whether the soil is dry or wet). Once the seedlings have survived, watering can be reduced. Replace dead seedlings promptly. When planting, line up the holes in straight lines using the middle of the holes as the point, to facilitate ventilation.

3. Fertilizing: Rosemary is fairly tolerant of poor soil. During the seedling stage, according to different soil conditions, apply a small amount of compound fertilizer after cultivating and weeding. After fertilizing, cover the fertilizer with soil. After each harvest, apply a quick-acting fertilizer, mainly nitrogen and phosphorus fertilizers; generally apply 15 kg of urea and 25 kg of ordinary superphosphate per mu.

4. Pruning: Rosemary can be pruned 3 months after planting and surviving. Excessive hard pruning often causes the plant to be unable to sprout again. A relatively safe practice is not to cut more than half the length of the branch each time you prune. Although small buds appear in every leaf axil of the rosemary plant, and these axillary buds will develop into branches as the branches extend in the future, once the plant grows larger, the branches grow sideways, which not only looks messy but also makes poor ventilation likely to lead to damage from pests and diseases. Therefore, regular pruning and training are very important.

5. Harvesting: Rosemary can be harvested for many years after one planting. Harvesting is mainly for branches and leaves, which can be cut with scissors or directly broken off by hand. However, special attention must be paid to the fact that the sap flowing from the wound quickly turns into a sticky gum that is very difficult to remove, so gloves and long-sleeved clothing must be worn when harvesting. The number of harvests can depend on the growth situation; generally 3-4 harvests can be made each year, and each harvest yields at least 250-350 kg per mu.

6. Pests and diseases: In humid environments, root rot, gray mold and other diseases are common on rosemary. If the plant wilts while the growing medium is still moist, the plant needs to be moved out of the greenhouse immediately. The most common pests are red spider mites and whiteflies, and the most ideal method is biological control. Emphasis should be placed on prevention, starting with sanitation, proper water management, reasonable temperature and light, and frequent observation to promptly remove diseased and weak plants.