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 irrepressible nature of much of the vegetation you will find on invasive plants lists, including Oriental bittersweet, is due to the vigor of the rhizomes of these aggressive plants. One reason why it is so difficult to eradicate an invasive plant that uses rhizomes to propagate itself is that, from a piece of rhizome left behind in the soil (after you have tried to dig the plant out, for instance), a new plant can emerge. Examples of aggressive and/or invasive plants that spread out of control with the help of rambunctious rhizomes include:
Thuggish Landscape Plants That Spread via Rhizomes
But it is not just weedy plants that can spread via rhizomes. Some of the attractive plants that we use in landscaping share this quality with the unattractive plants listed above.
For example, despite their pretty little bell-shaped flowers, which are quite aromatic, many gardeners consider lily-of-the-valley plants problematic due to their invasive rhizomes. Golden hops vine 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:
Tip: If you see "creeping" in a plant's common name and/or "reptans" in its botanical name, that is often a good indication that the plant uses rhizomes to store nutrients and to propagate itself vegetatively. It is also a possible red flag for gardeners who value low-maintenance landscaping and do not want to be saddled with rhizomatous (the spelling for the adjective) plants that will be constantly popping up in spots where they are not wanted.
It should be noted, however, that rhizomes are not always a bad thing. There are some well-behaved plants that have rhizomes, such as canna lilies. Also, sometimes you actually want a plant to spread. The very name, "ground cover" is often used with the implied meaning that such a plant will spread out over a large area, thereby suppressing weed growth. The rhizomes of the popular ground cover, Pachysandra terminalis allow the plant to do just that.
Rhizomes vs. Roots, Stolons
Rhizomes and stolons (for example, grass stolons) are similar plant parts but distinguished from each other by the fact that 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.
Was this article helpful? If so, you may also wish to read 10 Worst Plants to Grow in Your Yard.