How to Grow Colored Calla Lilies? A Detailed Guide to the Latest Growing Methods

Colored calla lilies are the collective term for species and hybrid cultivars in the genus Zantedeschia (calla lily) of the family Araceae, other than the white calla lily. They originate from central and southern Africa and are commonly used to make bouquets, flower baskets, garlands and vase arrangements. Dwarf and small-flowered cultivars grown in pots are used to decorate steps, windowsills, balconies and in front of mirrors, as companion plantings in courtyards, and in clumps beside ponds or rock piles. Now let us take a look together at how to grow colored calla lilies!

Growth Habits of Colored Calla Lilies

Colored calla lilies fear both cold and heat and high temperatures. In hot seasons the above-ground parts wither and the underground rhizomes enter dormancy. Most calla lilies go dormant during the low-temperature period in winter. If the temperature is suitable, they can bloom year-round, but tubers replanted after dormancy bloom most profusely. In greenhouses in the north, the flowering period runs from November to May of the following year. Cut flowers keep well in water, with an ornamental period of 15 to 20 days in winter and 7 to 10 days in summer. They require loose, well-drained, fertile or slightly clayey soil.

Propagation Methods for Colored Calla Lilies

1. Division: After the main flowering period of colored calla lilies or after dormancy, dig out the tubers of vigorous clumping parent plants. According to the size of the original tubers and the number of buds, divide one clump into 2 to 3 clumps (each clump must have 2 to 3 buds), plant them separately and manage them normally; they will bloom in 3 months.

2. Daughter corms: Dig out the tubers during dormancy, and after normal division, some smaller tubers can also be cut off. These small tubers must be cultivated in the open field for 1 to 2 years before they can become flowering corms. Before the ground freezes in autumn, prepare the land and make beds, and use ordinary garden soil to grow the daughter corms. Daughter corms grow slowly; if a culture medium is used instead, most daughter corms can form flowering corms in the same year.

3. Sowing: Because colored calla lilies have a relatively low natural seed-setting rate, seeds are not easy to obtain. If propagating by sowing, select and keep vigorous parent plants and carry out artificial supplementary pollination; the seeds can be harvested once mature. Sow immediately after harvesting. The suitable germination temperature is around 20°C, and sprouts emerge in about 4 weeks. Transplant when there are 2 to 3 true leaves. Under excellent cultivation and management conditions, flowering corms can be produced in two years.

Growing Methods for Colored Calla Lilies

1. Soil: For growing calla lilies, the potting soil should preferably be a sandy, acidic soil with good aeration and drainage. It is best to place a layer of coarse sand grains at the bottom of the pot to benefit the growth of the calla lily, then mix in one third garden soil and leaf mold, and add a small amount of organic fertilizer. It is best to choose a shallow pot for planting calla lilies.

2. Temperature: Calla lilies like a semi-shaded environment, so avoid placing them under strong light. The optimum temperature for calla lily growth is 22 to 30°C. Below 20°C, the growth rate of calla lilies slows down and may even stop. Calla lilies like warm, humid environments, so when overwintering, special attention must be paid to keeping them warm.

3. Watering: Calla lilies are similar to other potted plants; watering them depends on how dry the potting soil is. Before watering, first check the condition of the potting soil. Normally, you can spray water on the surface of the potting soil and on the flowers to keep the soil moist. During the growing period they like plenty of water, so frequently sprinkle water on the leaves and the ground, and pay attention to keeping the leaves clean.

4. Fertilizing: Phosphorus and potassium fertilizers are suitable for fertilizing calla lilies. Fertile soil is beneficial to their growth, so apply dilute fertilizer frequently to ensure the potting soil has enough nutrients. For those who want to save seeds, it is recommended that after the calla lily sets fruit, spray it with monopotassium phosphate solution once every 10 days at a concentration of 0.1% to 0.2%.

5. Light: During growth, calla lilies relatively prefer a warm, shade-avoiding environment, but note that calla lilies at different growth stages have different light requirements. During the growth stage, calla lilies are fairly shade-tolerant. When they are in the vigorous growth period, they need abundant light conditions.

6. Disease and pest prevention: When ventilation is poor during the growing season, calla lilies are most prone to aphid damage. When pests occur, spray 40% omethoate emulsion at 1500 to 2000 times dilution for control, and pay attention to improving ventilation conditions.

Precautions for Colored Calla Lilies

1. Be careful with fertilizer amounts: During the growing period, fertilize calla lilies once every 20 days, using decomposed bean cake water. In the peak growing season, apply more dilute fertilizer, once every 10 days. Apply nitrogen, phosphorus and potassium fertilizer solution to calla lilies. Be sure to avoid pouring fertilizer water in from the leaf sheaths, as this will cause calla lilies to rot. Too little fertilizer may cause yellowing of the leaves due to malnutrition, while too much fertilizer can also cause yellow leaves on calla lilies. After fertilizing, rinse with clean water.

2. Pay attention to the planting season: Calla lilies enter dormancy in June and July. At this time, the corms around mature plants can be removed to grow new potted plants. The most suitable season for growing them is August and September. Division propagation must be done in autumn, otherwise it will be difficult for them to bloom that year; even if they do bloom, the flowering period will be late.

3. When do they bloom: February to April is the flowering season for calla lilies. Note that sufficient light must be given for them to produce pure, healthy flowers. If the temperature is suitable, they can bloom year-round, but tubers replanted after dormancy bloom most profusely. In greenhouses in the north, the flowering period runs from November to May of the following year. Cut flowers keep well in water, with an ornamental period of 15 to 20 days in winter and 7 to 10 days in summer.

4. Management during dormancy: After the flowering period ends, calla lilies will enter dormancy. At this time, reduce the amount of watering, especially after May when the plants begin to turn yellow and wither. Indoors, attention should be paid to ventilation and keeping them dry to prevent tuber rot. When the plants are completely dormant, the tubers can be taken out, dried and stored, then planted again in autumn.

5. Toxicity of calla lilies: Calla lily flowers are toxic, containing large amounts of raphides (calcium oxalate crystals) and alkaloids. Accidental ingestion can cause symptoms of poisoning such as drowsiness. This species is listed as a non-toxic plant in the Chinese plant atlas database, but its toxicity lies in the tubers, spathes and spadices; chewing a small piece of tuber can cause swelling and pain of the tongue and throat.

6. Promptly renew old leaves: During the peak growth and flowering period, if the leaves are too lush, crowded and poorly ventilated, promptly peel off the outer old leaves whose flower stems have already been drawn, cutting them off from the base. The purpose is to avoid excessive leaves affecting light and ventilation, promote flower stem growth and increase yield. If there are not many old leaves but the new leaves are too vigorous, with poor internal ventilation and few flower stems, you can also carry out leaf-pulling treatment, gently pressing the leaves toward all sides so that the clump spreads out. Combined with reasonable water and fertilizer measures, this can increase flower production.