Dog-strangling vine (Cynanchum rossicum)
Dog-strangling vine (DSV), also known as pale swallowwort, belongs to the Milkweed family (Asclepiadaceae). It is a non-native perennial, twining vine from Eurasia. The vines can grow up to 2m in height, and have small pinkish to dark maroon flowers that start to appear in late May to early June. Opposite leaves are ovate, dark green, smooth, and shiny. The seed pods begin appearing in late June and are mature by mid to late July. Each pod produces numerous wind-borne silky-haired seeds.
Reproduction
DSV can reproduce by seed and by its massive underground root system (rhizomes). The seed is extremely viable once it germinates and the rhizomes can also propagate many new plants.
Ecological threat
DSV grows well in the sun, the shade and all soil conditions, making it extremely difficult to control. The vines can form dense colonies, smothering short plants, and can grow over small shrubs and trees causing deformities and possibly death.
In some instances old-field habitats occupied by goldenrods and grasses are replaced almost exclusively by pale swallowwort, disrupting natural succession and completely altering the physical structure of those habitats.
Management options
-
Ploughing and planting
- Infested land might be brought under control by ploughing and planting an annual crop until the seed soil bank is depleted, possibly as long as five years.
- Mowing and mulching
- Mow the plants in mid to late June, when the pods are starting to appear, to help stop seed production. Covering the area with mulch helps to stop the sprouting of new plants from the rhizome.
Warning!
The sap of this plant can cause an allergic reaction in some people.
Wear gloves when handling it and
wash exposed skin with soap afterward. |
Disposal of the plants
For small infestations, seed pods and roots can be placed in paper bags to dry out, and then burned in a fire pit. Another method is to boil the seeds for at least ten minutes to ensure that they will never germinate. You can also store the seeds in water until they rot (several months). The rest of the plant, the stalk and leaves, can be composted.
For larger infestations, the seed pods and roots, or whole plants, can be placed in heavy-duty plastic garbage bags and kept until they can be safely burned in a fire pit. Another option is to add water to the garbage bags and leave them out in the sun for a few months. The resulting stew can then be disposed of safely in compost piles.
Green matter will not be picked up by the municipality during the collection of household waste. Dispose of it in a compost pile if possible, or keep it until late fall or winter when it can be burned safely in a fire pit.
Useful links:
Photos:
|
