Looking for a fast-growing, easy-care, tropical showstopper? Colocasia esculenta makes a statement in the garden or as a houseplant. In this article, we share everything you need to know about growing and caring for Colocasia plants.
I. Appearance and Characteristics
Taro (Colocasia esculenta) is a root vegetable. It is the most widely cultivated species of several plants in the family Araceae that are used as vegetables for their corms, leaves, stems and petioles. Taro corms are a food staple in African, Oceanic, East Asian, Southeast Asian and South Asian cultures (similar to yams). Taro is believed to be one of the earliest cultivated plants.
Colocasia esculenta is thought to be native to Southern India and Southeast Asia, but is widely naturalised. Colocasia is thought to have originated in the Indomalayan realm, perhaps in East India, Nepal, and Bangladesh. It spread by cultivation eastward into Southeast Asia, East Asia and the Pacific Islands; westward to Egypt and the eastern Mediterranean Basin; and then southward and westward from there into East Africa and West Africa, where it spread to the Caribbean and Americas.
Colocasia esculenta is a perennial, tropical plant primarily grown as a root vegetable for its edible, starchy corm. The plant has rhizomes of different shapes and sizes. Leaves are up to 40 by 25 centimeters (15+1⁄2 by 10 inches) and sprout from the rhizome. They are dark green above and light green beneath. They are triangular-ovate, sub-rounded and mucronate at the apex, with the tip of the basal lobes rounded or sub-rounded. The petiole is .8–1.2 meters (2+1⁄2–4 feet) high. The path can be up to 25 cm (10 in) long. The spadix is about three fifths as long as the spathe, with flowering parts up to 8 millimeters (3⁄8 in) in diameter. The female portion is at the fertile ovaries intermixed with sterile white ones. Neuters grow above the females, and are rhomboid or irregular orium lobed, with six or eight cells. The appendage is shorter than the male portion.
Taro is related to Xanthosoma and Caladium, plants commonly grown ornamentally, and like them, it is sometimes loosely called elephant ear. Similar taro varieties include giant taro (Alocasia macrorrhizos), swamp taro (Cyrtosperma merkusii), and arrowleaf elephant’s ear (Xanthosoma sagittifolium).
II. How to Grow and Care
Sunlight
Elephant ears can be planted in full sun to partial shade, but they prefer growing in a part-shade or dappled sun location. Cultivars with darker leaves need more sun to maintain their color. The more sun you give elephant ears, the more you will have to water them.
Temperatures and humidity
Colocasia likes warm weather and lots of humidity. You will see the most growth from your plant when the temperatures range from 68°-86°F, but they are relatively tolerant of temperatures over 50°F. When the temperature drops below 40°F, expect little growth from your plant. A frost will do significant damage to foliage.
Most types of Colocasia are cold hardy to zone 8, and some will even overwinter in zone 7 if provided a healthy layer of mulch to protect the roots. I live in zone 8, and while my Colocasia plants die back in the winter, they come back stronger and bigger every year.
Colocasia likes warm weather and lots of humidity. You will see the most growth from your plant when the temperatures range from 68°-86°F, but they are relatively tolerant of temperatures over 50°F. When the temperature drops below 40°F, expect little growth from your plant. A frost will do significant damage to foliage.
Most types of Colocasia are cold hardy to zone 8, and some will even overwinter in zone 7 if provided a healthy layer of mulch to protect the roots. I live in zone 8, and while my Colocasia plants die back in the winter, they come back stronger and bigger every year.
Watering
Colocasia plants need a lot of water. These wetland plants need to have consistently moist soil. Without enough water, it will wilt, and the leaves may turn brown. Root rot is not usually a problem. They can tolerate and truly crave ample watering.
Once established, it will be a bit more drought-tolerant, as the leaves act as a shield over the soil around them. The shade provided by their very large leaves helps the soil to retain moisture.
Soil
The best soil type is loose, nutrient-dense, and able to hold moisture. Good drainage is never bad, but these plants can thrive in a swamp, so the main concern is moisture and nutrients.
A mixture of clay or loam with compost and a slightly high acidity level will be the most appropriate soil for your Colocasia. Adding worm castings to your soil is a great option, as they can hold up to ten times their weight in water.
Fertilizing
Colocasia is a heavy feeder. It needs lots of nutrients in the soil, so it is best to enrich the soil before planting to give your plant the best start. You can fertilize this plant regularly without the risk of overdoing it.
A standard 20-20-20 fertilizer can be administered as often as weekly. However, every other week is less likely to drain through the soil quickly, reducing the risk of accidental fertilizer pollution in groundwater.
Planting Instructions
Pruning
This plant benefits from regular pruning for health and aesthetic appeal. Damaged leaves can lend an unhealthy appearance to your plant and invite fungal or bacterial diseases. It is best to trim off any damaged foliage, cutting these stems down to about 2” from the base of the plant.
As the leaves age, they will naturally droop. To maintain the plant’s appearance, trim them off using a clean, sharp blade or a pair of sharp, sterile pruning shears.
In winter, after the first frost has killed off the foliage, trim off all the leaves down to about 6” from the base of the plant. If allowed to thaw, these leaves will become soft and be at risk of rotting and causing harm to the root system. In preparation for spring, you can remove the last bits of dead or dried-out foliage.
Propagation
Colocasia is very easy to propagate, and if you desire to expand the space where they are planted, it can be done quite quickly. Propagation can be done in 3 ways:
- Division of the main corm
- Separating offsets
- Cutting the tubers
Corm Division
This method takes the most time and has a lower success rate than others, so it is typically the least popular. Dividing the main corm involves digging up the main corm and dividing it into pieces.
You can use a sharp, sanitized knife to split the corms. Each piece should have a developing eye.
Plant these portions of the corm in propagation trays, maintain continuous moisture, and wait for each eye to become a new plant.
Separating Offsets
Colocasia plants produce offsets fairly freely. If they remain attached, these offsets will typically not grow as large as the mature portion of the plant. Once detached and allowed to grow independently, they should grow as large as the parent plant.
If your plant is mature, healthy, and visibly producing suckers, lift it from the soil. Use your hands or sharp pruners to remove the offset tuber suckers and replant them in a container just like their mother plant.
Cutting Tubers
If you want to harvest the roots of your Colocasia (Taro), this is the most effective propagation method. When you dig up your corms at the end of the season, cut a portion of the corm attached to the above-ground growth.
Re-pot these portions of corm in pots and allow them to grow over the winter. In the spring, they will return as if the corm had not been severed.
Pests and Diseases
Common Pests & Plant Diseases
Fungal Leaf Blight
The most common elephant ear plant disease is fungal leaf blight. It can be treated if caught early. If the plant is infected with this fungus, it can cause tell-tale lesions that may ooze fluid and turn purple or yellowish. It can also cause fuzzy growth on the leaves. If left alone, it can infect the entire plant. To treat it, remove collapsed leaves.
Pythium Rot
Pythium rot is often the result of soil remaining saturated for several days or weeks. It may appear as yellowing in spots or distinct patches on the leaves or stem. If you pull the root structure out of the ground, the root will appear dark and greasy.
A plant with this kind of root rot is not salvageable, and you should pull it out entirely. If your plant was in a container, discard all the infected soil and sterilize the pot.
Spider Mites
Spider mites like this plant for the shade potential and the texture of their leaves. Spider mite damage looks like tiny yellow or brown spots on the leaves. An infestation can lead to leaf drop and stunted growth. Another sign of spider mites is webbing found on the plant. To get rid of spider mites, you can use a steady stream of water from a hose to wash them off. Apply insecticidal soap or horticultural oil as organic methods to keep them away.
Common Problems
Elephant ear plants are easy to grow, fast-growers, and aren’t susceptible to many problems. However, since they’re water lovers, fungal infections are their biggest threat.
Leaves Start Yellowing
If the leaves turn yellow, it could mean they need more or less sunlight, water, or fertilizer. Alternatively, the plant may be going dormant for the season. Cut back the yellow leaves and wait for them to return next spring.
Drooping Leaves
Elephant ears droop if light, water, or fertilizer levels are off. Large leaves can also droop if they become too heavy, and you can remedy their weightiness with stakes to support the plants. Plants will also decline if temperatures are too cold for them.
Stunted Leaves or Pale Leaves
Often deformed, smaller, or pale leaves signify that your plant needs more nutrients, light, or water. Move your plant, provide more water, or provide fertilizer.
Wilting
Wilting is a sign that the plant is getting too much sun or heat exposure and not enough water. Consider moving your plant to a shadier spot and schedule its watering more frequently.
Maintenance
Colocasia will multiply yearly, which can become a nuisance if you want to keep them contained. If possible, new plants should be removed from the main root to prevent them from regrowing during the season.
If you prefer to allow them to spread, they require very little additional maintenance. Keeping damaged foliage trimmed will help your plant look its best.
III. Uses and Benefits
- Culinary uses
Taro is a food staple in African, Oceanic and South Asian cultures. People usually consume its edible corm and leaves. The corms, which have a light purple color due to phenolic pigments, are roasted, baked or boiled. The natural sugars give a sweet, nutty flavor. The starch is easily digestible, and since the grains are fine and small it is often used for baby food.
In its raw form, the plant is toxic due to the presence of calcium oxalate, and the presence of needle-shaped raphides in the plant cells. However, the toxin can be minimized and the tuber rendered palatable by cooking, or by steeping in cold water overnight.
Corms of the small, round variety are peeled and boiled, then sold either frozen, bagged in their own liquids, or canned.
- Ornamental uses
These large ornamental types of bulb plants can be very impressive when placed and grown outside in a sheltered location during the summer.
Especially in northern locations, elephant ear plants provide a very tropical landscape look even for a short period and make good additions near water gardens.
Elephant ears can live outdoors all year in USDA Hardiness Zones 8 – 11. In these year-round growing areas, some consider the elephant ears to be an invasive plant.
In northern climates, they can be treated more as annuals, where the elephant ears bulbs, corms, or tubers are stored over winter for the next growing season.