How to Grow Calla Lily (Zantedeschia, Araceae): Toxicity, Reasons for Not Blooming, and Precautions

The calla lily is also known as arrowleaf elephant ear flower, water taro, wild taro, arrowhead flower, calla lily, and flower taro. It is native to southern Africa and is a perennial bulbous flower of the Araceae family. So what are the cultivation methods and precautions for calla lily?

The calla lily is native to southern Africa and is a perennial bulbous flower of the Araceae family. It has a rhizome and basal leaves that are heart-shaped-arrow-shaped or arrow-shaped, 15-45 cm long, green, with long petioles. The peduncle rises above the leaves, and the spadix is cylindrical. The spathe is 10-25 cm long in total, slightly trumpet-shaped, mostly white, but also yellow or pink. It blooms twice a year, the first time in February-March and the second time in August-September. Calla lilies can be grown in pots for ornamental display, the cut flowers last a long time without wilting, and they can also be used medicinally.

Cultivation Methods for Calla Lily

1. Soil selection for growing calla lily

Calla lily is best planted in a fairly deep clay or purple sand pot with a diameter of 30-40 cm. It likes to grow in deep, fertile, loose, slightly acidic sandy loam, and the potting soil can be made by mixing leaf mold, garden soil, and fine sand in a 6:3:1 ratio.

2. Fertilization methods for growing calla lily

Calla lily likes fertilizer. From leaf growth until before it blooms, apply light fertilizer frequently, about once every 10 days with a nitrogen, phosphorus, and potassium compound liquid or granular fertilizer. When fertilizing, be careful not to drip liquid fertilizer on the leaf surface, as this can cause rot; do not apply nitrogen fertilizer alone, to prevent too many leaves and few or no flowers. Applying ferrous sulfate as a top dressing can make the leaves larger, thicker, greener, smooth and glossy, and the petioles less prone to growing, thereby keeping the leaves attractive while also promoting flower bud formation and prolonging the flowering period. The specific method is: dilute ferrous sulfate into a 7% solution and apply it once every month, watering thoroughly each time.

3. Watering methods for growing calla lily

Calla lily likes moisture. After it grows leaves, from mid-autumn to the following spring it should be watered regularly, keeping the potting soil on the moist side without becoming waterlogged, and the leaves should also be misted frequently while the nearby ground is sprinkled with water to increase air humidity and help its growth. However, whether misting or sprinkling, avoid getting water on the flowers and prevent water from flowing into the leaf center, otherwise it can easily lead to soft rot of the leaves. In winter, use water close to room temperature for watering and misting. In late May, the amount of watering should be reduced to encourage dormancy; after the leaves turn yellow, stop watering and place the calla lily in a cool, ventilated place where it will not be exposed to rain.

4. Temperature requirements for growing calla lily

The suitable growing temperature for calla lily is 15-25°C. Below 10°C the flowering period is delayed, below 5°C growth stalls, and at 0°C it may die. In spring, it should be moved out of the shed when the lowest temperature is steadily 10°C.

5. Light requirements for growing calla lily

Calla lily likes sunlight and long light exposure, but dislikes strong light. From leaf growth in mid-autumn until flowering in winter and spring, it should receive plenty of sunlight, especially after being moved into the shed in winter, when it should be given full light and kept above 10°C. It begins to push out buds from New Year's Day to before Spring Festival, and reaches peak flowering in March-April. Insufficient light in winter delays the flowering period, or the plant only pushes out buds without blooming, and the buds may even gradually turn green and shrivel. In late May, move it to a ventilated, shady place. The high-temperature period in summer is its dormancy period, so reduce watering and fertilizing, and provide appropriate shade when the sunlight is strong.

6. Potting methods for growing calla lily

Potting or repotting and changing the soil is best done from mid-August to mid-September after the Start of Autumn. Too early, and the dormancy period is short and the small offset tubers from tillering are not yet plump, affecting growth; too late, and the flowering period is delayed and shortened. When potting, place a layer of crushed hard plastic foam blocks at the bottom of the pot to improve aeration and drainage and prevent root rot, and add some bone meal and nitrogen, phosphorus, and potassium compound fertilizer to the potting soil. When planting, select thick, strong tubers with buds, plant 4-5 buds per pot, and cut off the aged part at the base of the tuber and the small sprouts that emerge around it. Plant 3-5 plants per pot, with the buds facing upright, and cover with soil a little more thickly. Then water, place in a shady spot, and after leaf buds grow, move to a place with ample sunlight.

7. Precautions for growing calla lily

(1) Calla lily is afraid of smoke. In winter, if it is placed in a room where coal is burned for cooking and heating and is exposed to smoke for a long time, a large amount of smoke will cover the leaves, causing yellow leaves or flower drop. Therefore, take care to place the flowerpot in a place with circulating air and no smoke to prevent smoke exposure.

(2) For dwarf cultivation of calla lily, paclobutrazol treatment can be used to significantly dwarf the plant and increase its ornamental value. Usually after it enters dormancy in summer, in combination with repotting and division propagation, mix paclobutrazol with a small amount of fine soil and sprinkle it around the plant, using 10-15 grams per pot depending on the size of the pot. Then water thoroughly and cultivate in a moist, shaded, well-ventilated place. At the same time, control fertilization, applying fermented liquid fertilizer once every 3-4 weeks.

(3) Be careful that fertilizer water is not poured on the leaves. After fertilizing, rinse immediately with clean water to prevent the branches and leaves from rotting. When the branches and leaves are lush, remove the outer old leaves to help the flower stalks emerge. February-April is the peak flowering period. After May the weather becomes hot and the plant begins to turn yellow and wither; stop watering, lay the pot on its side, let it dry out, and encourage dormancy. After all the leaves have withered and turned yellow, take out the tubers, dry them, store them, and plant again in autumn.

(4) In winter, if the temperature is around 5°C, do not water too much; it is best to keep the potting soil moist but on the dry side. If the temperature is above 10°C, the potting soil can be kept moist. For colored calla lilies placed indoors, mist the leaves and the surrounding area frequently throughout the growing season to increase air humidity.

8. Pest and disease prevention for growing calla lily

Calla lily is prone to mosaic disease during the growing period. When the disease occurs, mosaic patterns or chlorotic small spots appear on the leaves, yellow streaks form along the leaf veins, and the petals become variegated; in severe cases the leaves curl inward, become deformed, and even wither, and the plant becomes stunted, affecting flowering. Calla lily mosaic disease is caused by cucumber mosaic virus. This virus is spread mainly through sap contact and aphids. Disease resistance differs somewhat among varieties. Because calla lily is propagated by root division, it is relatively easy for this virus to be passed on year after year, worsening progressively. For prevention and control, carefully select virus-free rhizomes as material for division propagation. When diseased plants are found, remove and burn them promptly. Other host plants of cucumber mosaic virus should also be cleared to reduce disease spread. Spray insecticides such as malathion, carbaryl, and omethoate to control the aphids that transmit the virus.

9. Propagation methods for growing calla lily

(1) Division propagation

After the main flowering period or after the dormancy period, dig up the tubers of a vigorous clumping mother plant, and according to the size of the original tubers and the number of bud points, cut one clump into 2-3 clumps, each with 2-3 bud points, and plant them separately. With normal care, they will bloom after 3 months.

(2) Offset tuber propagation

Dig up the tubers during the dormancy period. After normal division, some smaller tubers will also be cut off. These small tubers must be grown in the open ground for 1-2 years before they can be used as flowering-sized tubers.

Precautions for Growing

1. Planting season for calla lily: Calla lily enters dormancy in June-July, and at this time the tubers around the mature plant can be taken to grow new potted plants. The best growing season is August-September. If division propagation is used, it must be done in autumn, otherwise it will be difficult to bloom that year or the flowering period will be late.

2. Toxicity of calla lily: The tubers, spathe, and spadix of the calla lily are all toxic, containing large amounts of calcium oxalate crystals and alkaloids. Ingestion by mistake can cause symptoms of poisoning such as coma, so be sure to remember this when growing it.

Reasons Why Calla Lily Does Not Bloom

1. Insufficient light

The calla lily plant still grows, but it tends to become leggy rather than plump and strong. Because there is not enough light, the leaves' photosynthesis is relatively poor, and it is very difficult to form flower buds, so blooming becomes difficult. It is recommended to move the calla lily to a bright environment with plenty of scattered light for care, while of course also avoiding strong light.

2. Overwatering

As the saying goes, moisture grows leaves and dryness grows roots. Whether watering is needed during calla lily cultivation should be determined by how dry the potting soil is, not by feeling. It is recommended to control the frequency of watering, and when watering, be careful not to pour water into the central part; this can avoid root rot and help the root system develop and mature, which is necessary for the possibility of blooming.

3. Lack of fertilizer

When cultivating calla lily, it is recommended to apply light fertilizer frequently, watering with dilute fertilizer solution (generally prepared by mixing granular compound fertilizer or decomposed manure with water, or using fermented soybean milk water, milk water, rice-washing water, etc.), especially increasing the proportion of phosphorus and potassium fertilizer, common ones being decomposed fish scales, bone meal, superphosphate, potassium dihydrogen phosphate, etc. Potassium dihydrogen phosphate can be diluted with water and sprayed on the leaves to increase the plant's absorption and utilization rate.

The Flower Language of Calla Lily

The flower language of the calla lily is universal love, holiness, piety, eternity, elegance, nobility, hope, purity, and pure, flawless love. Its elegant flower posture, clean flower appearance, and pure flower language are the beauty that the calla lily brings to love, and we too have more expectations for love.