Plants with Rhizomes: Definition, Examples

And How They Are Different From Roots, Stolons

Close up of stinging nettle (urtica) plant and leaves
Stinging nettle spreads via rhizomes.

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Rhizomes are modified stems running underground horizontally. They strike new roots out of their nodes, down into the soil. They also shoot new stems up to the surface out of their nodes. This rhizome activity represents a form of plant reproduction. These underground plant parts also store nutrients.

The pervasive nature of much of the vegetation you will find on invasive plants lists, including Oriental bittersweet (Celastrus orbiculatus), is due to the vigor of the rhizomes of these aggressive plants. A new plant can emerge from a small piece of a rhizome. It is challenging to eradicate an invasive plant that uses rhizomes to multiply if you inadvertently leave a bit of rhizome behind in the soil (after you dig the plant out). Examples of rhizomatous aggressive weeds and invasive plants that can spread out of control include:

Woman holding in hand rotunda fingerroot, the shape of the rhizome resembles fingers growing out of center piece.

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Landscape Plants That Spread via Rhizomes

Attractive landscaping plants can enjoy vigorous growth, much like unattractive, weedy plants. Desirable plants can spread via rhizomes too. For example, many gardeners consider the pretty little aromatic, bell-shaped flowers of lily-of-the-valley plants (Convallaria majalis) problematic due to their invasive rhizomes. Golden hops vine (Humulus Summer Shandy) is another specimen whose beauty is marred by vigorous rhizomes that make the plant an ill-behaved member of its gardening community. There are numerous other examples, such as:

In each case, you will have to decide for yourself whether the beauty of a plant that spreads by rhizomes offsets its tendency to become a nuisance. Some gardeners put up with the invasive quality of bugleweed because they admire its pretty flowers or foliage, but others regard it as one of the worst plants to grow in the yard.

Tip

If you see "creeping" in a plant's common name or reptans or radicans in its Latin name, that is often a good indication that the plant uses rhizomes to store nutrients and multiply without using seeds. It is also a possible red flag for gardeners who value low-maintenance landscaping and do not want to be saddled with rhizomatous plants that will constantly pop up in spots where they are not wanted.

In the end, it may come down to how much control you need to have over precisely what is growing across each square foot of your property. If you are the type who can't stand to see a weed growing anywhere on the lawn, then you should avoid growing plants with rhizomes at all costs.

How to Plant Rhizomes Safely

If you love a rhizomatous plant but worry about it overgrowing or overwhelming your other garden plants, install a physical barrier in the soil that the rhizome can't grow past, like a container buried underground. If your plant has shallow roots, you can take any plastic container and remove the bottom, which gives your plant more drainage. However, be wary of deeply rooting rhizomes like Japanese knotweed, which can grow 10 feet deep. Knotweed can grow past almost any container.

Rhizomes are wonderful if you want to grow a plant precisely so that it will spread and fill in bare spots in problem areas where other plants will not grow well. A plant has to be tough to serve this purpose. So, while its ability to spread is regarded as vigorous in certain instances, that same ability may be a godsend in others. Some well-behaved plants are Tropicanna canna lilies (Canna 'Phasion') and German iris (Iris germanica); both are valued in the landscape and wanted to multiply.

The term "groundcover" implies that a plant will spread out over a large area. Most can suppress weed growth or fight erosion on a slope, like the popular groundcover Pachysandra terminalis.

Rhizomes vs. Roots, Stolons

Rhizomes and stolons (for example, grass stolons) are similar plant parts but distinguished from each other because stolons remain above-ground, while rhizomes do their spreading underground.

To distinguish rhizomes from roots, remember that rhizomes, unlike roots, are modified stems. As such, they bear nodes from which brand-new plants can spring.