What to Do When Alocasia (Araceae) Leaves Turn Yellow and Droop
Alocasia, also known as black-leaf taro or black-leaf alocasia, is a perennial herbaceous foliage plant of the genus Alocasia in the family Araceae. It prefers a warm, humid, semi-shaded growing environment. During cultivation, its leaves often turn yellow and droop. What causes this? What should be done about it? Let us take a look together below!
Growth Habits of Alocasia
Alocasia prefers semi-shade and must never be exposed to strong direct sunlight. It likes warm, humid environments. The optimum growing temperature is 25-30°C; in winter the temperature should not fall below 15°C. From March to September it is 22-27°C, and from September to the following March it is 16-22°C. Below 15°C, growth stalls and the plant enters a dormant state. It is tolerant of water and moisture; during the growing season the potting soil should be kept moist, and an air humidity of 70%-80% is favorable for leaf growth and development. When the potting soil is dry, the leaves become soft and droop, but they quickly recover after watering, so it also has a certain resistance to drought.
Alocasia Leaves Turning Yellow and Drooping
1. Improper watering: incomplete watering, too little watering, or too much watering can all cause Alocasia leaves to turn yellow and droop. Especially during the high-temperature period in summer, leaf moisture evaporation is high and water demand is greater; a lack of water very easily makes the leaves wilt, so the foliage must be sprayed with water frequently while keeping the environment humid, but waterlogging in the pot must be avoided, otherwise it will cause root rot.
2. Lack of nutrients: Alocasia leaves turning yellow and drooping may also be caused by a lack of nutrients. It can be saved by promptly supplementing with decomposed dilute fertilizer, compound fertilizer, and similar fertilizers, but the amount must be small, 2-5 granules.
3. Lighting problems: after overwintering, being in a hurry to move the plant outdoors and placing it in a warm spot to bask in the sun means it cannot adapt to the sudden climate change for a time. Or long-term weak lighting can also cause Alocasia leaves to turn yellow and droop. It should be moved to a bright place in time, but avoid prolonged direct sunlight.
4. Other causes: keeping Alocasia for a long time in an environment with poor ventilation, not spraying and cleaning the leaf surface for a long time, accumulation of dust, and blocked photosynthesis can also cause the leaves to turn yellow and droop.
How to Care for Alocasia
1. Temperature: Alocasia prefers a warm, humid, semi-shaded growing environment. The optimum growing temperature is 20-30°C, and the overwintering temperature is 15°C.
2. Propagation: Alocasia is commonly propagated by division. Generally, when temperatures are higher in spring and summer each year, divide plants whose underground tubers have tillered and grown densely along the separation points of the tubers, so that each part has 2-3 plants, then pot them separately. When dividing, damage the roots as little as possible. After potting, place them in a shaded, humid environment, keep the potting soil constantly moist, and pay attention to misting the leaves to help the new plants recover growth. You can also dig out the underground tubers in spring before new buds sprout, cut the tubers into sections, disinfect and preserve the wounds with plant ash or sulfur powder, let them dry slightly, then wrap them in sphagnum moss, or place them in loose soil that drains and aerates, so that they grow adventitious roots and sprout new shoots. During this period, the substrate must never be too wet, lest the tubers rot. This plant can also be propagated by sowing, but the seeds are not easy to obtain.
3. Soil: For potted Alocasia, a loose, well-drained, well-aerated soil rich in humus is suitable. Generally, equal parts of leaf mold, garden soil, and river sand mixed together can be used as the substrate.
4. Watering: April to September is usually its vigorous growth period. At this time it requires moist soil and relatively high air humidity, and should be given sufficient water; especially during the high-temperature period in summer, leaf moisture evaporation is high and water demand is greater. If water is lacking, the leaves very easily wilt, so the foliage must be sprayed with water frequently while keeping the environment humid, but waterlogging in the pot must be avoided, otherwise it will cause root rot. In autumn, when the temperature falls below 15°C, Alocasia's growth stalls and it enters a dormant state, and the aboveground leaves begin to gradually wither. At this time, the amount of watering must be reduced as much as possible, and the plant should be placed in a warm, windless, dry place, keeping the potting soil appropriately dry (only slightly moist) to help it overwinter safely; if humidity is high and the temperature is low, the tubers very easily rot.
5. Light: Alocasia prefers semi-shade and must never be exposed to strong direct sunlight. In a semi-shaded environment, the leaf color is fresh and tender and full of luster, the veins are clear, and the leaf color is dark green. If the light is too strong, the leaf color easily becomes dull, eventually causing sunscald, with rough leaf surfaces, grayish-white leaf color, blurred veins, and sometimes scorched spots on the leaf surface; but too weak light also easily causes leggy growth, with the plant growing slender and tending to lodge. During the vigorous growth period, according to the plant's growth, apply a dilute liquid fertilizer 1-2 times a month, and additionally apply phosphorus and potassium fertilizer, to help the stems stand upright and grow robustly, and at the same time to help the underground tubers grow plump and resist cold for overwintering.
Note: The whole Alocasia plant is toxic, with the stems being the most toxic. Skin contact with the sap causes itching, contact of the eyes with the sap causes blindness, and accidental ingestion of the stems or leaves causes itching and swelling of the tongue and throat, drooling, burning pain in the stomach and intestines, nausea, vomiting, diarrhea, sweating, and convulsions; in severe cases, suffocation and death from cardiac paralysis. For ordinary home cultivation, what needs attention is the toxicity of Alocasia. Try to avoid growing it in households with children, and also be careful during care; be sure to prevent children and uninformed people from accidentally ingesting it or taking it in through other channels.