Roundleaf Greenbriar


Roundleaf Greenbriar (Smilax rotundifolia) forms thick stands in woodland areas and can invade wetlands. The plant’s leaves are dark green and shiny. Small whitish-green 5-petal flowers form clusters appear in May. These flowers are not showy but have an extremely long bloom time. Fruit color is a showy reddish-black to purplish-black. The plant is widely sold as an ornamental. Hand pulling can, with care, work to eradicate it locally, especially when there is a small number of vines. This form of removal creates patches of disturbed soil into which other plants will move.

The leaves of roundleaf greenbriar have a waxy look that is quite glossy. They grow along a thorny vine, turning yellow in the fall. Notice the tendril wrapped around an older vine in the upper left center of the photo.

These thorns, alternating around the stem, are quite pronounced.

Roundleaf greenbriar can form dense, impenetrable patches either following the ground profile or using its tendrils to climb up other plants.

Roundleaf greenbriar is known by other names: Common greenbriar, Common catbriar, Bullbriar, Horsebriar. Once established in an area, it forms dense thickets.

  9 Responses to “Roundleaf Greenbriar”

  1. Greenbrier is a NATIVE plant!!! see
    It is listed more recently as a native in Harris’s Flora of Essex County, 1975. Where did you get information listing it as non-native in New England? I’ve heard people wrongly state that poison ivy is a non-native plant just because of its aggressive nature, but never greenbrier.

    Walter Kittredge, Senior Curatorial Assistant, Harvard University Herbaria

    • Quite correct. The sentence referred to stated that it is an invasive pest in the northeast, not that it is non-native. However, by starting the sentence with a statement that the plant is native to the southeastern United States, anyone might infer that it is non-native in the northeast, which it is not. The offending sentence has been removed. Thanks for pointing this out.
      for the Conservancy,
      R. French

  2. […]  I wonder if they have any value for the woods or if they just suck the life out of everything?  I’ll have to look that up.  Also found a tick crawling on me.  Flushed […]

  3. can this be poisonous? I believe this is what I was cleaning out of the fence-row that now has me all broke out and itchy, like poison ivy. I know what poison ivy looks like and did not see any of it, so quite certain it came from something else. I remember this vine as it stuck me several times as I was getting it off the fence.

    • My apology for being so frightfully late in replying to your question. the answer is that round leaf greenbriar is not poisonous. The thorns are rather nasty though.

  4. […] A good article about this thorny vine can be found here: Roundleaf Greenbriar […]

  5. This invasive vine is taking over my hedgerows and choking everything in it’s way. Will round-up, applied with a sprayer on the leaves, kill the roots?

  6. […] Greenbriar is a plant that is native to the state, but it is a problem for ranchers and farmers in the state . . . and well as to residents of out-in-the-boonies properties that have a lot of trees on them.  The vining plant has thorns on it, and they are sharp and easily cut you in run-ins with thickets of the vines low to the ground. […]

  7. Greenbrier is sometimes a nuisance, but it does not belong on this list because it is native: MIPAG defines invasive plants as “non-native species that have spread into native or minimally managed plant systems in Massachusetts, causing economic or environmental harm by developing self-sustaining populations and becoming dominant and/or disruptive to those systems.”