Mexican Flame Vine (Senecio confusus): How to Grow and Overwinter at the Cold Edge

How-To & Propagation · Mexican Flame Vine · The Southeast

A tropical vine that blazes orange from June until frost, grown at the cold edge of the map. Here is how to bring Mexican flame vine through a Carolina winter, and how to hedge the bet.

8 min read · By Fiona von Grey · Aiken, South Carolina

I.A daisy that climbs

Most people are surprised to learn that Mexican flame vine is a member of the daisy family. Look closely at a flower head and the family resemblance is plain: a ring of orange rays around a golden center, each head about an inch across, held in clusters at the tips of the stems. The color deepens as the flowers age, from a clear tangerine to a red-orange, so a vine in full flower carries two or three shades at once, like coals at different stages of burning. In the middle South the show runs from about June until frost, and the bees and butterflies find the vine within days.

The plant is a fast, twining evergreen vine native from Mexico through Central America into tropical South America. In a garden, expect 6 to 12 feet of growth in a season on a trellis, a fence or a shrub willing to be climbed. The leaves are alternate, coarsely toothed, somewhat fleshy and shaped like an arrowhead, two to four inches long, and they make a good dark ground for the flowers.

We sell the vine under the name the trade knows, Senecio confusus, and that is the name most gardeners search. Botanists moved the species out of Senecio in 1950, and the accepted name today is Pseudogynoxys chenopodioides. Both names carry a small story. Senecio comes from the Latin senex, old man, for the white, hair-like tufts on the seeds. Pseudogynoxys means a false Gynoxys, a related Andean genus the vine resembles, and chenopodioides means like a goosefoot, a nod to the leaf shape.

II.Reading the zone map honestly

This is a tropical plant, and the reliable sources say so. In zones 10 and 11 the vine stays evergreen and flowers much of the year. In zone 9 the top is cut back by frost and the plant returns from the base. University of Florida guidance treats the vine as an annual in zones 8b and 9, and the Missouri Botanical Garden gives zones 9 and 10, "possibly zone 8" with winter mulch. Aiken sits in zone 8a. That puts every one of our garden plants on the cold edge of the range.

We would rather tell you that plainly than round the number up. In a mild winter a well-sited, well-mulched crown in zone 8a may come back. In a hard one the plant may not. Nobody can promise which kind of winter is coming, so the craft lies in setting up the odds and keeping a spare.

III.The October routine, step by step

None of this is difficult, and most of the work happens in the few weeks before the first frost, which in Aiken usually arrives in November.

1. Take insurance cuttings now. Before the nights turn cold, cut a few healthy stem tips four to six inches long. The stems root readily, and in the wild the vine roots wherever a node touches the ground. Strip the lower leaves, stick the cuttings in a small pot of moist, free-draining mix, and keep the pot warm and bright but out of hard sun. Rooted cuttings on a cool windowsill are the cheapest winter insurance you will ever buy.

2. Or layer a stem into a pot. If cuttings feel fussy, bend a low stem down into a pot of soil set beside the vine, pin the stem at a node, and wait. In three or four weeks the stem will have rooted, and you can sever the new plant and carry the pot indoors.

3. Let the frost do the first cut. Leave the vine standing until the first hard frost blackens the foliage. Cutting a tender plant back hard while the weather is still mild can push soft new growth just in time for the freeze.

4. Mulch the crown deeply. Once the top is down, pile four to six inches of loose mulch over the base of the plant, pine straw or shredded leaves, and widen the mound a foot or so beyond the stems. The goal is to keep the crown and the upper roots from freezing hard. We leave the frosted stems in place over winter: they hold the mulch, they mark the spot, and they cost nothing.

5. Be patient in spring. Clear the dead stems once the danger of frost has passed. A dieback perennial returning from the root after a cold winter can be slow to show, so give the crown until early summer before you write the plant off. If nothing appears, plant one of the insurance cuttings into the same spot and you are back in business.

IV.Siting the vine for next summer

Where you plant a marginal vine matters as much as how you mulch the crown. A south- or west-facing wall stores the day's heat and gives some back overnight, and a planting bed tight against the foundation often runs a few degrees warmer than open ground. Good drainage counts too: crowns of tender plants generally suffer more in cold, sodden soil than in cold, dry soil, so avoid the low spot where water stands in January.

Give the vine something to climb. The stems twine and scramble, so a chain-link fence, a trellis of wire or a sturdy shrub that will not mind a summer guest all serve well. Pair the orange with blue and purple for a late-season border that hums: a Mexican bush sage alongside (we wrote about the salvia in The Sage That Saves the Best for Last) and the red of Turk's cap nearby, whose own story we told in The Hibiscus That Never Opens.

V.Honest cautions

One honest caution comes with the color, and the caution concerns vigor rather than cold. Where winters never knock the plant back, the vine can run. In Hawaii the species has naturalized and is rated a high-risk invader, smothering other plants and seeding freely, and University of Florida writers call the vine aggressive in south Florida, though the plant is not on the state's invasive list. In the middle South, frost keeps the vine in hand. Gardeners in frost-free places should site the plant where the runners can be watched.

Two smaller notes. Many plants in the old Senecio group contain pyrrolizidine alkaloids, but none have been reported from this genus, and no specific toxicity is documented for the vine. Some gardeners do find the sap irritating to skin, so wear gloves for a big cutting session, and keep pets from chewing the plant. And the vine is not salt-tolerant, so the sea wall is the wrong place for the plant, however much the orange would suit the view.