There are two varieties: The pale swallow-wort (Vincetoxicum rossicum), which comes from the Ukraine; and the black swallow-wort (V. nigrum) that originated from southwestern Europe. In their natural environments, both varieties are kept in check by native natural enemies, particularly insects and diseases. The vines are unique in that they contain strong and unusual poisons that limit natural enemies and keep deer and cattle from feeding on them.
How to Control Swallow-Wort
- Ensure early detection and total weed removal--for sample photos, visit Invasive.org.
- Do not remove in the fall when seeds could be dispersed.
- Thoroughly clean any mowers that moved through patches of swallow-wort in the fall.
- If there are pod-bearing plants on your property, remove them carefully (without dispersing the seeds) and destroy them by either bagging and taking to a landfill, or burning.
- Plow and plant an annual crop until the seed soil bank is depleted, which can take as long as five years.
- Mowing does not get rid of swallow-wort but it can be used to prevent the plant from going to seed.
- If digging up the plants, the complete root crown must be completely removed before the seeds ripen.
- Weed removal is difficult: Swallow-wort's root system (massive, running deep and wide) must be manually pulled or dug out. Buds on the root crown easily re-sprout after mowing.
- For very large infestations, herbicides (such as Garlon 4 [triclopyr ester] or Roundup Pro [glyphosate]) have been effective. Spraying must be done only after flowering has begun, not before.