Calla Lilies: Basics, Types, Growth & Care

Zantedeschia aethiopica, also known as Calla Lily, Arum Lily, and Water Lily, is a perennial robust herb in the family Araceae. The plant features a tuberous stem and somewhat thick, arrow-shaped leaves, typical of the Araceae family, with a unique spadix. Its natural blooming period starts from November and can last until May or June of the following year, with a peak blooming period in March and April.

The entire flowering period lasts for 6-7 months, and when in full bloom, the flowers resemble horse hooves. Notably, the entire plant, including its tuberous stem, inflorescence, and spadix, is toxic, containing large amounts of calcium oxalate crystals and alkaloids, which can cause symptoms of poisoning such as drowsiness if ingested.

Basic Introduction

The Calla Lily, also known as Water Lily, Wild Arum, Buddha’s Lotus, and Goddess Lily, is a member of the Araceae family. It is a common flower used in bridal bouquets in Western countries and is the national flower of Ethiopia. It prefers a warm climate, cannot tolerate cold or high temperatures, and thrives at around 20°C. At 0°C, the tuberous stems will freeze and die.

In winter, it requires plenty of sunlight; insufficient light leads to fewer flowers, though it is slightly shade-tolerant. In summer, when the sun is too intense and scorching, it should be properly shaded. It likes damp conditions and can tolerate a little waterlogging, but not drought. It prefers loose, fertile, humus-rich loamy soil.

The Calla Lily is elegantly majestic, with pristine white flower buds resembling horse hooves, and verdant leaves adorned with white spots. This combination of attractive flowers and leaves has made it one of the important cut flower varieties in the international flower market.

It is commonly used to create bouquets, flower baskets, flower wreaths, and vase arrangements, all of which have excellent decorative effects.

Growth and Distribution

Growth Environment

The Calla Lily prefers a warm, damp environment with plenty of sunlight. It cannot tolerate cold or drought. Its ideal growth temperature is between 15-25°C, with nighttime temperatures not lower than 13°C. If the temperature rises above 25°C or falls below 5°C, it is forced into dormancy.

The Calla Lily likes water, so the soil should be kept moist during its growth period. Watering should be controlled after the tuber enters dormancy during the hot summer months. The soil should be fertile, with good water retention, and clay loam soil, with a pH value between 6.0-6.5, is preferred.

Distribution Range

It is cultivated for ornamental purposes in many areas of China. Its original habitat is in northeastern and southern Africa.

Morphology and Features

Zantedeschia aethiopica is a perennial robust herb with a tuberous stem. Leaves are basal, petiole 0.4-1 (-1.5) meters long, sheathed at the base. The leaf blade is thicker, green, heart-shaped or arrow-shaped, with a pointed, tapered, or caudate tip, heart-shaped or trident base, entire, 15-45 cm long, 10-25 cm wide, without spots, with a posterior lobe 6-7 cm long. The flower stalk is 40-50 cm long and smooth.

The spadix is 10-25 cm long, with a short tube, yellow; the limb slightly reflexed, acute or tapered, with a conical tip, shiny white, sometimes with green. The cylindrical spadix is 6-9 cm long and 4-7 mm thick, yellow: the female inflorescence is 1-2.5 cm long; the male inflorescence is 5-6.5 cm long. The ovary has 3-5 compartments, tapering into the style, mostly surrounded by three staminodes.

The berries are short ovate, pale yellow, 1-1.2 cm in diameter, with a persistent style; the seeds are ovoid-spherical, 3 mm in diameter.

Cultivation Methods of Calla Lily

Pot Cultivation

1. Soil: The soil in the pot should be fertile, neutral or slightly acidic. You can use two parts finely crushed pond soil, one part leaf mold, add an appropriate amount of calcium superphosphate and well-rotted human and animal manure, and mix it all together.
2. Propagation: Usually after flowering, the small balls around the tuber are stripped and cultivated for a year, flowering in the following year. Through experiments, I have found that using the root suckers division method can allow the plant to flower in the same year.
3. Specific Method: From late June to early August, combine with repotting, and manually separate the well-developed large division with roots and plant it in the prepared pot. If used for cut flowers, you can plant 2 to 3 divisions. After planting, place it in a cool place. Using this method of propagation, flowers can bloom from September to October of the same year.

Management

1. Light and Temperature: Calla Lily likes a warm, humid, and slightly shaded environment, but it needs plenty of sunlight during flowering, otherwise the spadix will be green, affecting its quality. Ensure 3-5 hours of light every day, otherwise, the petiole will elongate and affect the ornamental value. Calla Lilies are not cold-resistant, so they should be moved into a greenhouse in mid-October. In the summer, they need to be in a shaded environment, often sprayed with water to cool and moisturize.
2. Watering and Fertilizing: Calla Lily likes a humid, fertile soil, commonly referred to as “heavy feeding and watering,” during the growth period, it needs to be watered more. Top dressing can use a rotation of matured bean cake water and other liquid fertilizers with chemical fertilizers, applied every two weeks. When applying liquid fertilizer, avoid watering the fertilizer into the leaf sheath to prevent rot. It used to be said: “Stop fertilizing when you see flower buds”. After comparative experiments, I believe that the amount of fertilizer should be increased after seeing the buds to ensure a long flowering period, larger and brighter flowers, and constant budding for year-round flowering.
3. Use of Ferrous Sulfate: In pot cultivation of Calla Lily, the application of ferrous sulfate is an important part of the experiment. Applying ferrous sulfate can make the leaves of Calla Lily grow larger, thicker, greener, smooth, and glossy, the petiole is not easy to elongate, thus ensuring the beauty of the leaves. It can also promote the formation of flower buds and prolong the flowering period. The specific method is: dilute the ferrous sulfate into a 2% solution, apply it once every month, each time thoroughly watering the plant.

Taboos

1. Avoid low temperatures and dry conditions. The Calla Lily (Zantedeschia aethiopica) prefers warm and humid environments, and is not cold resistant. Indoor temperatures during winter should not drop below 10°C to ensure successful blooming. During the plant’s growth and flowering period, ensure the soil remains moist and frequently mist the leaves with warm water to maintain their fresh green appearance.
2. Avoid smoke and dust pollution. The Calla Lily requires clean air for healthy growth and flowering, and is particularly sensitive to smoke. Exposure to smoke from stoves or oil can hinder its growth, causing yellow leaves and flower drop.
3. Avoid inadequate light. The Calla Lily enjoys ample light during both its growth and flowering periods. Particularly around Chinese New Year when it’s blooming, insufficient light can lead to unopened flower buds falling off the plant.
4. Avoid poor ventilation. Poor indoor ventilation during winter often results in an infestation of scale insects, accompanied by sooty mold. When the number of scale insects is small, they can be brushed off gently. For sooty mold, wipe off the black sooty powder with clean water. If severe, apply a 1:1500 dilution of Tobujin or Carbendazim to control the problem.

Propagation Methods

The primary method of propagating Calla Lilies is by division of bulbs. After the plant enters dormancy, remove the small bulbs around the rhizome for replanting. Seeds can also be sowed for propagation. Once the seeds mature, they can be sowed in pots. The optimal germination temperature is around 20°C.

Dividing: After the flowers fade in May or June and new leaves start to appear as old leaves wither, or in mid-September when repotting, detach the small bulbs around the parent plant and pot them separately. Generally, flowers will bloom three months after planting.

Sowing: Indoor pot sowing is predominant. The suitable germination temperature is 18-24°C, and germination occurs 15-20 days after sowing. Seedlings require 3-4 years of nurturing before they can bloom.