Cassava (Manihot esculenta) and yucca (Yucca L.) share a few similarities. All these are part of the subkingdom Tracheobionta, or vascular plants, and are classed as Magnoliophyta, or flowering plants. However, cassava and yucca are not exactly the exact same plant. The confusion can stem from cassava frequently being referred to as yucca. However, cassava belongs to another family and genus than yucca plants, and every one has different cultural requirements and attributes.
Appearance
Cassava plants are hardy in U.S. Department of Agriculture zones 8 through 11, while yuccas typically thrive in zones 5 through 11 based on the species. Cassava is a tropical perennial that grows to about 10 feet tall. However, in frost-free areas, this plant may grow to heights of around 20 feet. Cassava has smooth, erect stems and large dark green leaves which have reddish-colored veins and creamy yellow markings that persist throughout the growing season. The leaves are compound with seven leaflets, and the edible tuberous roots are about 8 to 30 inches long. Yucca plants are tree-like perennials, growing to heights between 4 and 40 feet tall. The stiff, blue-green leaves are big like cassava, but distinctive in appearance, with yellow margins along with a spiky, dagger-like form. The flower spikes produce bell-shaped, whitish flowers.
Family and Genus
Cassava plants are part of the family Euphorbiaceae and the genus Manihot. The Euphorbiaceae family consists of mostly herbs, shrubs and trees. It’s one of the largest plant families, containing about 7,500 species of crops. The genus Manihot consists of trees, herbs and shrubs grown for their showy foliage and edible roots. Yucca plants are part of the yucca genus, which consists of plants which are prized for their decorative, sword-like leaves which vary in size, shape, and shades of green or blue. Yuccas are members of the family Agavaceae, which consists of plants which produce rhizomes. This family is commonly known as Agave, and includes the genera Dracaena and Sansevieria.
Culture
Cassava requires full sun along with a minimum of eight months of warm weather. This plant doesn’t tolerate flooding and in drought states will likely decrease its leaves to preserve moisture, but it might thrive in a range of adverse soil conditions, and requires very little care or maintenance. Cassava plants are propagated by planting stem segments. Yucca plants also need full sun, but tolerate partial shade and adapt to many different soil conditions, though they prefer rich, moist soils. Yuccas may be propagated from seeds, or grown from rhizomes, stem cuttings or from offsets taken from plants that were established. A distinct difference between cassava plants and yucca plants is the way each is pollinated. While cassava may be pollinated by various insects, yucca has a mutualistic relationship with the yucca moth. In this relationship, the yucca plant is only pollinated by this moth and one cannot survive without the other.
Toxicity
While parts of both plants are edible, cassava roots must go through thorough processing due to the existence of toxic components such as cyanogenic glucocides, linamarin and lotaustralin. All parts of the cassava plant contain cyanogenic glucosides, however, the highest concentrations are in the leaves, and those are poisonous to both human and animals. Yucca plants are not as poisonous as cassava, however, the roots of Buckley’s yucca (Yucca constricta) contain saponins, which can be poisonous to humans. However, they are usually poorly absorbed from the body and do not result in irritation unless a person is allergic to them.