Recently, I was walking along Morgan Creek in Chapel Hill, not far from the North Carolina Botanical Garden, when I noticed what I took to be an unusually extensive and dense population of Hexastylis arifolia, the little brown jug.
Closer inspection revealed that the plants were actually Cyclamen hederifolium, a native of Mediterranean Europe. The plants were growing on a steep hillside, where rocks and loose soil have slowly slid down the slope. A few plants extended onto the wetter, more compacted soil of the flood plain, but that was clearly not their favored habitat.
Nearby were a few plants of the real Hexastylis arifolia.
These Cyclamen hederifolium plants had clearly escaped from cultivation, but I don’t think they can really be considered invasive. The true invasives are plants that form dense stands, choking out native species–things like Eleagnus species, Ligustrum sinense (Chinese privet), Hedera helix (English Ivy), Pueraria montana (Kudzu), and Microstegium vimineum (Japanese stiltgrass).
Cyclamen seeds are distributed by ants, so the plants are unlikely to spread as far as those species with windborne seeds or berries that are eaten by birds. The relatively sparse and low-growing leaves of C. hederifolium are also unlikely to smother other woodland plants–not that there is much else that likes to grow in the dry, unstable soil that the cyclamens seem to favor.
Not far from the cyclamens, I did see several other species with more potential to be invasive. Mahonia bealei (leatherleaf mahonia) and Ilex cornuta (Chinese holly) were naturalized in the woods, and of course, English ivy is ubiquitous. The beautiful variegated leaves of Arum italicum stood out in the wet soil near the creek. I had been thinking of adding A. italicum to my garden, but given its ability to spread and potential to be invasive in the mid-Atlantic region, I’m now not sure that’s a good idea.
Although the C. hederifolium are probably no threat to native ecosystems, seeing them in an ostensibly wild area was a good reminder that the plants we grow in our gardens may not always stay there.