Rhizome

A rhizome is a horizontal stem whose nodes can produce both roots and new aerial shoots. Its stem identity is shown by features including nodes, internodes, scale leaves, terminal or lateral buds, and vascular tissues arranged as in a stem rather than a typical root.¹ Rhizomes may lie beneath the soil, rest on its surface, or occupy waterlogged substrates. They range from thin, creeping structures to thick organs packed with starch and water.

The term describes a growth form rather than a single plant lineage. Ferns, grasses, sedges, irises, ginger, turmeric, lotus, and many other plants possess rhizomes, although their anatomy and ecological roles differ. Short rhizomes produce dense clumps, whereas elongated ones enable a plant to colonize space over several growing seasons.

Rhizomes help plants persist and spread by combining underground growth with dormant buds. A growing rhizome extends from its tip, while nodes behind the tip can form roots and shoots; portions separated from the parent may therefore establish independent plants when they retain viable buds.² This vegetative reproduction produces genetically identical ramets, though mutations and occasional sexual reproduction preserve variation within populations.

Many rhizomes also function as storage organs. Seasonal plants such as Zingiber officinale store carbohydrates and other reserves underground, then draw on them for renewed shoots. Rhizome dormancy can protect buds from cold, drought, fire, grazing, or burial, but survival depends on species, depth, soil conditions, and the duration of the stress.

Rhizomes are economically important as foods, spices, medicines, ornamentals, and sources of planting material. Ginger and turmeric are culinary rhizomes; lotus rhizomes are eaten in several cuisines; and bamboo, couch grass, and many lawn grasses spread through rhizomatous stems. Horticulturists divide rhizomes to propagate irises, cannas, and other ornamentals, generally ensuring that each division contains a healthy bud and enough stored tissue.

Rhizomatous growth can also make plants difficult to control. Some invasive or persistent species regenerate from small fragments, so cultivation, excavation, and disposal practices must prevent viable pieces from being redistributed. In restoration ecology, rhizomes can stabilize soil and support rapid recovery after disturbance, while in agriculture they may compete with crops for light, water, and nutrients.³

Rhizomes are not always completely underground, and not every underground storage organ is a rhizome. A stolon is a usually horizontal stem that commonly grows above ground and roots at its nodes, whereas a rhizome typically persists as a main stem beneath or close to the soil. Tubers such as potatoes are swollen stem portions, but their enlarged form and limited extension distinguish them from the usual creeping rhizome habit.¹

Rhizomes also shape plant communities in subtle ways. A network may connect shoots temporarily, permitting resource movement or shared support before older segments decay, while clonal growth can allow a plant to occupy patches that would be difficult to recolonize from seed. In bamboo, underground rhizome architecture helps determine whether a species forms compact clumps or spreads aggressively through long-running stems.⁴

Node

A point on a stem from which leaves, buds, roots, or branches may arise.

Internode

The stem segment between two successive nodes.

Stolon

A usually horizontal stem, often above ground, that can root and produce new plants at its nodes.

Ramet

An individual unit of a clonal plant connected to, or derived from, a larger genet.

Tuber

A swollen storage organ, commonly a stem or root, containing reserve nutrients.