Dragon's blood tree

Author: Zhang Lugu
Publisher:
Publish Date: 2003-01-01
Features: Hydroponic cultivation of Dracaena
Hydroponic cultivation of Dracaena involves using water as the medium, directly planting Dracaena plants in containers filled with water, or applying the necessary nutrients during the growth of Dracaena for indoor greening and decoration. Dracaena plants can have their cylindrical stems cut into segments of 10–20 cm in length. The upper end should be waxed to prevent moisture evaporation, and then placed in a container filled with water. Soon, new roots will grow from the lower part, and new buds will appear at the top, forming a good ornamental effect. Hydroponic Dracaena columns mainly rely on the nutrients stored in the stem segments for growth, typically with a lifespan of about 2–3 years. The first year of growth is the most vigorous, but as nutrients are gradually consumed, the original firm stem segments will gradually soften, the bark will become loose, and the leaves will turn from green to yellow, losing their ornamental value. However, if they are promptly planted in soil, they can continue to grow and be ornamental. For Dracaena species with cut stems for renewal, leafy tips can be hydroponically propagated. After insertion into water, new roots and leaves will emerge within about one month, while leafless stems may take 2–3 months to root and sprout leaves. The roots of Dracaena are slightly yellow or orange. If placed in a transparent glass bottle, the orange-yellow roots contrast beautifully with the foliage above. Linear-leaved Dracaena species can also be hydroponically propagated by cutting short branches during renewal pruning and placing them in water. Lucky bamboo is one of the most suitable species for hydroponic cultivation. Residents in Hong Kong, Macau, and Guangdong, among other places, often place several stems in bottles for home decoration. When hydroponically cultivating lucky bamboo, suitable stem segments can be cut and placed in water. The lower end of the cutting should be cut at an angle to facilitate water absorption. New roots will emerge within 10–15 days. The roots of golden-edged lucky bamboo are orange-yellow, which is very aesthetically pleasing and adds vitality to the room. Some Dracaena species can also be hydroponically cultivated by washing the roots of potted plants. This involves washing the roots of potted plants to remove soil or other substrates, and then proceeding with hydroponic cultivation. Suitable plants for this method include lucky bamboo, Sun God, and Starlight. The success of hydroponic cultivation of Dracaena species depends critically on water changes. This is especially true during stem cutting and when roots are washed from potted plants to be hydroponically cultivated. During growth, plant roots continuously perform respiration, consuming oxygen in the water, which gradually reduces the oxygen level and affects plant growth, potentially leading to failure. For hydroponic Dracaena, daily water changes are required for stem cutting and root washing, while for plants already rooted and adapted to hydroponic conditions, the frequency of water changes should be adjusted according to seasonal changes. Since the dissolved oxygen in water is inversely proportional to temperature—higher temperatures result in lower dissolved oxygen—the plant's oxygen consumption, which is proportional to temperature, increases with higher temperatures. Additionally, microbial reproduction accelerates at higher temperatures, leading to water quality deterioration. Therefore, more frequent water changes are recommended in hot weather, while longer intervals can be used in cooler weather. Generally, water should be changed every 3–5 days in summer, every 5–7 days in spring and autumn, and every 10 days or so in winter. During water changes, the roots should be rinsed with clean water, and sticky residues should be removed by hand. Old and rotten roots should also be trimmed. Hydroponic Dracaena placed in well-lit areas may develop algae on the container, which should also be cleaned. Roots not only fix the plant and absorb water and nutrients but also absorb oxygen from the medium. Therefore, when changing or adding water, the water level should never be filled to the brim, allowing some roots to remain above water. This ensures that roots can absorb dissolved oxygen in the water and also take in oxygen from the air. Only by fully meeting the plant's oxygen needs during growth can it thrive healthily. As with other substrates, fertilization is a crucial task for the normal growth and development of hydroponic Dracaena. Although tap water contains some mineral elements, these are far insufficient for the plant's needs. To ensure healthy growth, nutrients must be supplemented promptly according to the plant's developmental requirements. Fertilization should be performed regularly. Hydroponic Dracaena should be fertilized with hydroponic nutrient solutions. These solutions are formulated based on the plant's nutrient requirements in terms of concentration and pH, containing both macronutrients and micronutrients essential for growth. Therefore, it is difficult for general hobbyists to prepare them independently. For hydroponic Dracaena, it is best to use specialized nutrient solutions for flowering plants. When applying nutrient solutions, follow the instructions carefully and avoid indiscriminate use to prevent fertilizer burn. Fertilization of hydroponic Dracaena is best done during the vigorous growth periods of spring and autumn. In winter, Dracaena enters dormancy and generally does not require fertilization. In summer, growth slows due to high temperatures, and the plant's tolerance to fertilizers decreases, so fertilization should be stopped to prevent harm. For green-leaved Dracaena, nitrogen fertilizer is the primary nutrient, supplemented with phosphorus and potassium. For Dracaena species with colored spots or stripes on their leaves, more phosphorus and potassium should be applied to enhance the vibrancy of the colors. Fertilization can also be performed through foliar feeding, using a spray bottle to apply diluted fertilizer directly to the leaves. This can compensate for insufficient nutrient absorption through the roots. If leaf patterns become pale, spraying a 0.2% solution of phosphoric acid dihydrate can restore the plant's original vibrant colors. However, urea must never be added to the water. Urea is an artificial inorganic organic fertilizer. In hydroponic systems, which are sterile or low-bacteria environments, adding urea not only fails to provide the necessary nutrients but also allows harmful bacteria and other microorganisms to rapidly reproduce using urea as a carbon source, leading to contamination. Additionally, urea can cause ammonia poisoning or excess ammonium ions, harming the plant. Since Dracaena thrives in high humidity, frequent misting of the leaves can increase indoor humidity, promoting healthy growth. For hydroponic Dracaena in air-conditioned rooms, it is particularly important to maintain high humidity.
Pest and Disease Control
Root rot is caused by Phytophthora cactorum and often occurs in hot, humid seasons. Symptoms include irregular black spots on the phloem, with grayish-white or black mycelia. Severe cases lead to complete peeling of the phloem and black rot. The affected xylem appears waterlogged and slightly brown. The fungus spreads rapidly through the xylem, causing the rot to expand and forming numerous black mycelia at wounds. The disease primarily occurs at the potting soil interface of stems and trunks, often leading to plant rot and death. Symptoms may also appear on leaves, starting as small brown spots at the edges or damage sites, then expanding into irregular blackish-brown elongated spots with waterlogged edges. The disease progresses rapidly in humid conditions, potentially causing leaf death. During infection, spraying with 75% wettable chlorothalonil at 600 times the concentration or 70% wettable methyl at 1000 times the concentration can help control the disease. In hot, humid conditions, air circulation should be improved.
Leaf spot disease causes irregular bright brown spots on leaves, with violaceous edges and small black dots. The control method is the same as for root rot.
generally affects the tips of lucky bamboo, turning them grayish-white and expanding with brownish edges, severely impacting growth and ornamental value. Regular care should be provided to prevent excessive sun exposure. Infected leaves should be promptly cut and destroyed, and spraying with 50 or 75% wettable chlorothalonil at 800–1000 times the concentration can help control the disease.