Part of the large Spurge genus, cassava (Manihot esculenta) is a perennial, woody shrub that is native to South America.
Sometimes also referred to as yuca in the United States, it is not to be confused with the completely unrelated yucca plant.
Although not all that common in North America, the tuberous cassava root is a popular starchy carbohydrate food source in places like South Africa and Southeast Asia. Importantly, however, it must be cooked before being eaten as, in its raw state, and particularly with the bitter variety, it is toxic. The leaves are also edible and are high in protein, but they too need to be boiled before eating.
The roots are often boiled or roasted and are even sometimes turned into flour. Also sometimes called the tapioca plant, the tuber is used to produce tapioca pearls which are commonly used to make puddings.
Although the shrubby, large, green, palmate leaves can add some ornamental interest to a garden landscape, these plants are primarily grown so that the leaves and tubers can be harvested. You will only be able to grow the cassava plant as a perennial if you live in a warm region like Florida, where it is most similar to the tropical and subtropical climates it is grown in its native habitats.
|Botanical Name||Manihot esculenta|
|Common Name||Cassava, Manioc, Yuca, Tapioca|
|Plant Type||Woody Shrub, Perennial|
|Mature Size||Up to 4m. tall, Up to 3m. wide|
|Sun Exposure||Full Sun, Partial Shade|
|Soil Type||Sandy, Loam, Well-drained|
|Soil pH||Acid, Neutral, Alkaline|
|Bloom Time||Throughout the year|
|Hardiness Zones||8 - 12, USA|
|Toxicity||Toxic to people and pets when raw|
Cassava Plant Care
This isn't a plant that can be grown in regions that are subject to hard winters. But, if you can give it the warmth and sunshine it needs, you could end up with a bountiful crop of cassava roots for cooking. It grows quickly and is an interesting alternative to some of the more common root vegetables.
Some enthusiasts that do have colder winters will grow it in containers so that it can be overwintered indoors.
Although cassava plants produce their best harvest if they get extended exposure to sunlight, intense direct sunlight can cause leaf burn. In these instances, a partial shade environment would be better.
Cassava is known for being highly tolerant of a wide range of soils and pH levels, providing it is well-drained. For best results, however, a sandy, loamy option works well.
Part of the cassavas appeal is its ability to tolerate periods of drought and also heavy summer rains. Some cultivars, however, are more drought-tolerant than others, so you should do your research before planting. Standing water can cause root rot, so if you do live in a rainy region, the soil needs to have excellent drainage.
Temperature and Humidity
To ensure that a good crop is produced year-round, cassava needs to be in a primarily frost-free climate. They don't tend to do well in temperatures below 60°F or above 85°F.
Fertilization isn't necessary if you have planted your cassava in a fertile soil that is rich in organic matter. However, appropriate additional feeding can improve the yield you will get.
Their fertilization requirements are similar to those of the sweet potato. The fertilizer should be higher in potassium to prevent elongated, straggly roots. If you want a bumper crop of leaves, a fertilizer with more nitrogen will work better.
Is Cassava Toxic?
All parts of the cassava plant are toxic, so if you have kids or pets that try to eat the plants in your garden, this is not going to be the right plant for you. Only the cooking process kills the toxins present.
There are two types of cassava -- the bitter and the sweet varieties. The sweet one is the one more commonly grown as a commercial crop, and it is less toxic than the bitter version. However, often it is the bitter cultivars that are grown for ornamental purposes. Make sure you do your research before planting as the level of toxicity in a bitter variety can be as much as fifty times more than in the sweet type.
Both types, however, contain hydrocyanic acid and, when consumed raw, this can result in cyanide poisoning.
Roots and leaves must be properly cooked to eliminate the toxicity, with the bitter type needing at least 24 hours of soaking before the cooking process even begins.
Toxicity of Cassava: Symptoms of Poisoning
The symptoms of cyanide poisoning can vary dramatically depending on the amount that has been consumed. They can range from ataxia, vertigo, and vomiting, to collapse and death.
Without pruning, your cassava plant could begin to look rather leggy and straggly. If you are regularly harvesting for the leaves, it will be unlikely it will grow beyond one meter tall, but they can reach in excess of three meters.
To be sure that you are not accidentally growing the bitter cassava variety, it is best to propagate from cuttings rather than seeds. Stem cuttings from this plant root easily and quickly, and they can be planted directly into moist soil if the temperatures are right. You can expect the cutting to be fully established in just a couple of months.
If you live in a region prone to termites, this could be an issue for your cassava plant. The root crops can be quickly decimated by them.
The roots of a cassava plant only take about six months to become fully established. After this, if you have a good crop, you will likely be able to get a biannual harvest. When the leaves begin to turn yellow and drop, this is a good sign that the roots are ready to pull up.