I confess, I harbored a horticultural thug in my back yard for a couple of months, until a concerned neighbor informed me that the fence across my lower back yard had an invasive weed called black swallow-wort winding through it.

From walks in Two Lights Park, I knew that this nefarious horticultural thug would smother every low-growing plant in the area, and clamber up over shrubs as well. (Some stands of sumac in the park look like a stage set in a horror movie, with masses of this stuff winding up the trunks.) Plus, its wind-borne seeds spread far and wide, invading more gardens and yards. Do you suppose that’s what my neighbor was worried about?

Native viburnums and wild geraniums grow down near my back fence, and I wanted to save them from strangulation. Even more important, cardinals, chickadees, goldfinches and other songbirds eat the insects and berries that thrive on the other native plants growing there. They were all at risk. So down the hill I went, digging fork and plastic bag in hand.

Sure enough, I found milkweed-like pods dangling from twining vines bearing shiny, dark-green oval leaves. Black swallow-wort is related to milkweed, but researchers have observed that monarch butterfly larvae die when they eat it.

Like most invasive plants, getting rid of this stuff is difficult once it gets established. I almost never use pesticides on my property, but I admit I have made an exception for this particular weed.

The most effective method I’ve used is to pull the plants continually throughout the summer, then spray the young leaves of the surviving plants sometime in late August.

This takes regular monitoring, which isn’t always possible, but it does pretty effectively starve the fleshy roots, which are very resilient earlier in the season.

The other method, which is what I did in this case, is to wait until the seed pods have formed, but not yet opened. The plants with the most pods tend to be in sunny spots, and they become quite visible as the pods begin to turn yellow.

Dig up as much of the root as possible, or cut the entire plant down. Stuff all of the plant material in a heavy plastic bag, and either take it to a landfill or burn it.

My sealed bag full of swallow-wort will sit in a sunny spot in a corner of my garden until next spring, on the (unproven) theory that the temperature extremes and lack of light will reduce the amount of viable plant matter that goes to the landfill. (Just in case bits of the nasty thug somehow fall out of the bag along the way.) Stop black swallow-wort (and other horticultural thugs) from using your yard as a breeding ground.

Your neighbors, songbirds and monarch butterflies will thank you.

– Special to the Telegram