Periwinkle

The evergreen groundcover sold as creeping myrtle, and one of the most stubborn things in an American woodland. Its mats stop the spring wildflower layer cold. The useful news: it barely sets seed here, so it advances in a slow visible front you can actually beat.

How it takes ground rather than how to plant it: small glossy leaves in opposite pairs on wiry stems that root at every node, blue-violet pinwheel flowers in spring, and an evergreen mat that holds the soil surface against everything else in shade or sun.

You should not plant periwinkle, so what matters is recognizing it and understanding why it wins. It is a low evergreen trailing subshrub: wiry arching stems carrying small, leathery, glossy dark-green leaves in opposite pairs, forming a dense carpet three to six inches deep. Broken stems bleed a thin milky sap. In spring it produces solitary blue-violet pinwheel flowers about an inch across, five blunt petals set at a twist, on short upright shoots — white and plum-purple selections are also sold. Bigleaf periwinkle (Vinca major) is the same plant at larger scale, with leaves two to three inches long, hairy leaf margins and stems that arch a foot or more before touching down.

Its advantages over native ground flora are worth spelling out, because they explain why hand-waving control fails. It is evergreen, so it photosynthesizes through the winter and early spring while native perennials are dormant, and it shades the soil surface in every season. It roots at the nodes, so the colony is one connected organism with no seedling stage to fail. It is strongly deer-resistant because of its alkaloids, so in the over-browsed eastern woods deer eat everything around it and leave it alone. And it tolerates deep shade, drought, poor soil and total neglect. There is no site condition you can impose that disadvantages it, which is exactly why control has to be physical and repeated rather than clever.

It spreads by creeping and by people, not by seed. Every node that touches soil roots, a fragment left lying on the ground restarts the patch, and most wild infestations trace directly to dumped garden waste or an abandoned homestead planting.

Understanding how periwinkle moves is the whole control strategy, because it moves in only two ways and you can shut down both. The first is vegetative creep: the arching stems touch soil, root at the node, and the new crown sends out its own stems. A patch typically advances one to two feet a year in every direction, faster downhill and along moist edges. Because the colony is connected and each node is independently rooted, cutting the mat does nothing — you have removed leaves from a plant with hundreds of separate root systems underneath.

The second is people. Periwinkle rarely produces viable seed in North America, so it does not arrive on the wind or in a bird. It arrives in a wheelbarrow. The classic origin of a woodland infestation is a pile of garden clippings tipped over a bank, a load of divided groundcover given to a neighbor, or soil moved from a bed that contained it. Any fragment with a node will root, including pieces churned up by a tiller or dragged along by a mower deck. That is why the disposal rule is absolute: bag it, and put it in the trash or municipal green waste that is genuinely composted at heat. Do not compost it in a backyard pile, do not tip it over a bank, and clean tools and boot treads before you walk from an infested patch into clean woods.

Control, not care: cut the mat short so you can see the ground, roll and lift it like carpet with the rooted nodes attached, smother what you cannot lift for a full season or two, treat regrowth in the cold-season window with an on-label product, and hold the cleared edge every year.

Start by cutting the mat short with a string trimmer or a mower on its highest setting. This is not control on its own — periwinkle regrows readily — but it lets you see the ground and the rooted nodes, and it strips off the waxy evergreen leaf surface that otherwise sheds anything you spray. Then, while the soil is moist, rake and lift the mat like carpet: get a garden fork or a stiff rake under the edge and roll it back, pulling the rooted nodes up with it rather than snapping the stems off at the soil line. On small and medium patches this is the whole job. Follow with two or three passes over the next year to catch the nodes you missed, because you will miss some.

Where lifting is impractical — a big patch, or one laced through tree roots you should not disturb — smother it: cut it short, lay overlapping cardboard or several sheets of newspaper, and cover with four to six inches of wood chips. Give it a full growing season at minimum, and expect to need two, checking the perimeter monthly for stems escaping sideways. For herbicide, the practical extension recommendation reflects the waxy leaf: mow or trim first, wait three to six weeks for tender regrowth, then treat that flush while the plant is actively growing, using a product whose label lists your site — typically a glyphosate or triclopyr formulation — and following the label rates, protective equipment and restrictions exactly. The late fall to mild winter window is the good one: periwinkle is still green and active while nearby natives are dormant and cannot be harmed by drift. Plan on repeating the following year.

Finally, replant what you clear. Bare ground under trees invites the periwinkle back, or invites something worse. Good native replacements for shade include wild ginger, foamflower, green-and-gold, creeping phlox, golden ragwort, Allegheny spurge, partridgeberry, Christmas fern and woodland sedges. Ask a local native-plant nursery which of those suit your soil and light.

Answers for the reader who already has it: how to be sure it is periwinkle, why cutting fails, whether to spray, what to do about the neighbor's patch, and how many years this actually takes.

Is this periwinkle? A low evergreen carpet of small glossy dark-green leaves in opposite pairs on wiry trailing stems that root where they touch, with solitary blue-violet pinwheel flowers in spring and a little milky sap in a broken stem. In winter it is often the only green thing on the forest floor, which is the easiest confirmation of all. Is this the same as the periwinkle in the flower flats? No, and the distinction matters. The bedding annual sold as periwinkle or vinca in summer is Madagascar periwinkle, Catharanthus roseus, a different genus, a tender annual with pink or white five-petalled flowers and no creeping habit — it is not invasive in most of the country but it is considerably more toxic. I cut it back and it came straight back: expected. Every node under the mat is separately rooted, so cutting removes leaves from hundreds of intact plants. Cutting is a preparation step, not a control. Can I just smother it? Yes, with cardboard and four to six inches of mulch, but give it a full growing season and usually two, and watch the perimeter for stems running out sideways under the edge. Do I have to use herbicide? No. On a garden-sized patch, lifting the mat by hand and following up for two seasons works. Herbicide earns its place on large areas and on ground you cannot dig; if you use it, mow first, treat the regrowth, pick a product whose label lists your site, and follow the label. It is coming from next door: clear and hold a band a few feet wide on your side, check it twice a year, and talk to the neighbor — periwinkle only moves by creeping, so a maintained edge genuinely holds. How long will this take? Two to four years of decreasing effort for a typical yard patch, and you will win, because it cannot reseed itself back in. Is it dangerous to handle? Wear gloves: the sap irritates some skin, and the plant is toxic to pets and children if eaten. What do I plant instead? Wild ginger, foamflower, green-and-gold, creeping phlox, golden ragwort, Allegheny spurge, partridgeberry, Christmas fern or woodland sedges.

Vinca minor is the botanical source of vincamine, from which the supplement vinpocetine is made - but the cancer drugs people associate with the name come from a different genus entirely. There is no safe home preparation of this plant. Educational, not medical advice.

This section records how people have traditionally used this plant, and what is known about the risks. It is history and general information — not medical advice, and not a recommendation to treat anything. Plants are not dosed like medicines, some interact with prescriptions, and some are harmful in ways that are not obvious. Talk to a clinician before using any plant medicinally.

Two separate medicinal stories get tangled under the name periwinkle, and it is worth untangling them. Vinca minor contains vincamine, an alkaloid from which the semi-synthetic compound vinpocetine is manufactured; vinpocetine is prescribed as a drug in parts of Europe and sold in the United States as a nootropic supplement for memory and cerebral blood flow. The evidence for those claims is thin, and in 2019 the US Food and Drug Administration warned that vinpocetine should not be taken by women who are pregnant or who could become pregnant, citing reproductive-harm findings.

The other story belongs to a different plant. The chemotherapy agents vincristine and vinblastine come from Catharanthus roseus, Madagascar periwinkle — a separate genus that only shares the common name. Neither drug comes from the groundcover in your yard.

The practical point for a gardener is simple: there is no safe home preparation of periwinkle. The alkaloid content of the fresh plant varies wildly with age, season and growing conditions, the compounds are cardioactive and can lower blood pressure sharply, and there is no traditional dose you can trust. Do not make tea from it, do not tincture it, and keep it out of reach of children and pets. If vinpocetine interests you, that is a conversation for a clinician about a standardized product, not a reason to keep an invasive groundcover. This is educational information, not medical advice.

A Mediterranean plant carried across Europe for a thousand years as a symbol of remembrance, planted on graves and doorsteps, and brought to North America in the 1700s. A patch of periwinkle in the woods is very often the marker of a house or a burial ground that is otherwise gone.

Periwinkle has been travelling with people for a very long time. It was grown across medieval Europe as a garden and medicinal herb, wound into garlands, and associated so strongly with death and remembrance that it acquired names like flower of death and, in English, graveyard weed. It was planted on graves, at doorsteps and along the paths of old homesteads, and it outlived nearly all of them. Colonists carried it to North America in the 1700s for exactly those purposes, and nurseries have sold it continuously ever since as the reliable answer to dry shade.

That history has left a curious legacy for anyone walking in eastern woodland. Periwinkle almost never seeds itself, so a patch far from any road is not a natural occurrence — it is a record of habitation. Archaeologists and land trusts routinely use periwinkle, along with daffodils, yucca and old lilacs, as a surface indicator of a vanished farmstead, cabin site or family burial ground. If you find a mat of it deep in the trees, look nearby for a foundation depression, a chimney fall, a lilac, or the flat stones of unmarked graves. It is worth knowing before you start clearing, both out of respect and because it changes what you may want to disturb.

Vinca minor is invasive across the temperate East, Midwest and Pacific Northwest, roughly zones 4-8. Vinca major is the warm-climate problem, worst in California and the coastal Southeast, where it invades stream corridors rather than dry woodland.

Vinca minor is hardy roughly from zone 4 to zone 8 and escapes across the whole temperate East and Midwest, with heavy pressure in the Appalachians, the Ohio and Mississippi valleys, the mid-Atlantic and the Pacific Northwest. It appears on state invasive-plant lists in a long list of eastern and midwestern states — but those are mostly advisory lists maintained by invasive-plant councils and natural-resource agencies rather than regulatory ones, which is why it remains perfectly legal to buy in almost every state. Legality here is not a guide to consequences; check your own state and county list, and then decline to plant it regardless.

Vinca major is the warm-climate counterpart, hardy from about zone 7 to zone 10, and its damage is concentrated in California, the desert Southwest under irrigation, and the coastal Southeast. It behaves differently: rather than carpeting dry woodland, it invades riparian corridors — creek banks, canyon bottoms, irrigation ditches, damp shaded slopes — where it forms head-high mounded thickets, and where stem fragments broken loose by winter flows are carried downstream to found new colonies. In California it is a well-known problem in coastal canyons and along urban creeks. If you are in the West and you have periwinkle, check which species you have first, because a riparian V. major infestation spreads by water and needs the whole drainage worked from the top down rather than patch by patch.