It’s a bulb, right? Or wait, it’s a corm! What is a rhizome exactly? These questions may have crossed your mind when dealing with plants. Understanding the differences between bulbs, tubers, corms, and rhizomes can make you a better plant parent and gardener. So, let’s dig into the fascinating world of underground plant structures!
Seeds are familiar to most of us as the beginning of a plant’s life. However, bulbs, tubers, rhizomes, and corms are often collectively referred to as “bulbs” because they serve similar functions. These structures store food, water, and minerals as energy and give new life to the plant. They may look similar, but they have distinct characteristics.
Bulbs
True bulbs are globe-shaped, modified leaves that enclose a bud and store nutrients. They are often confused with corms, which are solid inside. Horticulturalists differentiate true bulbs from other types because they consist of layers of modified leaves and contain a miniature flower or sprout in the center. Examples of true bulbs include onion, garlic, amaryllis, shallots, tulips, daffodils, and lilies.
Corms
Corms resemble true bulbs but are actually swollen base stems that store food for the plant during dormancy. Unlike true bulbs, corms are solid and generally elongated with a membranous or scaly texture. When the parent corm has given all its energy, it is reabsorbed into the soil, leaving behind cormlets or cormels at the base of the shoot. These cormlets absorb and store nutrients, allowing corm plants to be divided and spread easily. Examples of corms include alocasia, elephant garlic, oxalis, fritillaria, crocus, and gladiolas.
Tubers
There are two types of tubers: root and stem. Root tubers are modified lateral roots that function as storage organs, while stem tubers are swollen stem roots. Stem tubers, such as potatoes, generally form near the soil surface and have nodes or “eyes” that develop into new plants. Root tubers, like carrots and sweet potatoes, absorb and store water and minerals while anchoring the plant to the soil. Both root and stem tubers have the ability to produce new baby plants. Other examples of tubers include yams, cyclamens, Jerusalem artichoke, anemone, and begonia.
Rhizomes
Rhizomes are horizontally growing, modified stems that produce both vegetative shoots and roots. They store starches and proteins, enabling plants to survive harsh underground conditions. Rhizomes can vary in size and shape and can grow above or below ground. Some rhizomes, like ginger or bamboo, have short internodes and form compact clumps, while others, like mint or horsetail, have longer internodes and spread quickly horizontally. Knowing which plants spread by rhizomes can help avoid unwanted invasions. Propagation is possible by dividing rhizomes into sections, ensuring each section has an “eye” or “button” from which new roots and leaves will emerge. Examples of below-ground rhizomes include snake plant, Venus flytrap, turmeric, ginger, bamboo, horsetail, and mint. Ferns and bearded iris are examples of above-ground rhizomes.
Propagation
Propagation methods for these plants include stolons, suckers, and offsets. Stolons are above-ground stems that creep along the surface of the soil, producing clones of the original plant once rooted. Examples of stolons are spider plants, strawberry plants, and many grasses. Suckers are side shoots or root sprouts that can live independently and are genetically identical to the mother plant. Banana plants can reproduce through suckers. Offsets, similar to suckers, grow from a bud at the base of the mother plant and are genetically identical. Many succulent plants, such as aloe vera, bromeliads, and hens and chicks, reproduce through offsets.
Understanding the different structures and reproductive methods of these plants can enhance your gardening knowledge and help you become a more successful plant parent. Happy growing!
Sending love,
Karina and Team SE
