New Invasive in Durham's Duke Forest Neighborhood

Here is an exhilarating but scary detective story about a pretty but ecologically dangerous plant. After finding Lesser Celandine (Ranunculus ficaria, also known as fig buttercup) in a yard in the Ellerbe Creek watershed, which feeds the Neuse River watershed, I described the plant to my friend Perry, who knows Durham and the NC piedmont very well. He said he had seen the species in a backyard in the Duke Forest neighborhood, which drains into the Cape Fear River. He had at first wondered if it was a rare wildflower, until he later saw it running rampant over a stream restoration site in Greensboro, NC.

When he showed me the plants he had seen in the Duke Forest neighborhood yard, I began tracking them upstream, using the instinct I had developed in tracking the similarly invasive Garlic Mustard in the Ellerbe watershed.

Close up, the plant looks like this. These flower stalks seemed longer than those in the Watts-Hillandale neighborhood yard.

Upstream were a series of larger patches. I felt like a sleuth in a detective movie, or maybe it was the primal rush of the hunt--something our minds evolved for but seldom have the chance to do.

When the brush became too dense, I returned to the road to explore further upstream. At Pinecrest and McDowell, I found one of the plants growing on the curb, an odd location since the rest of the infestations had been down along the stream bank. Note the storm drain that feeds straight into the floodplain of the creek this road crosses.

I looked down into the woods near this curb, and found the floodplain blanketed with the invasive, showing just how dominant and exclusionary of any other low-growing species it can become. Lesser Celandine has the potential to outcompete the many native species of spring wildflowers, and thereby impact the wildlife whose taste buds have not evolved to eat exotic plants.

Though the neighborhood has the protection of speed limits and Neighborhood Watch, there has been no one looking out for exotic plants that are able to invade gardens and speed downstream to infest natural areas.

Upstream of the intersection, the trail went cold, meaning that the infestation must have been entering the creek there from one of the side streets.

I followed a false lead to the left, then headed up McDowell Street. Near the top of the rise, I saw a hillside of yellow and knew I'd found the source of the infestation.

It's hard to predict how the homeowners are going to respond when you knock on their door and let them know they have an ecological menace growing in their yard. But this time, the news was very well received. At first they were puzzled, then tremendously thankful for having someone explain what was going on with this super aggressive plant.

They had liked the flower at first, but had grown increasingly concerned as it invaded the Vinca minor they had hoped would populate the hillside. The blue flowers of the Vinca can be seen amidst the sea of yellow in the photo. Though Vinca minor can also be thought of as an invasive, it doesn't spread downstream to new areas like the Lesser Celandine does.

We speculated that the seeds or perhaps the underground bulbules of the invasive had been washed down the driveway, then down along the curb until they reached the creek at the bottom of the hill, where they quickly began to spread downstream.

I had to return to New Jersey the next day, but Perry said he would track the flower downstream to determine the extent of spread. This sort of invasives work benefits from a Swat Team mentality, where swift action determines whether the invasion can be stopped while still limited in scope. Once the plant stops blooming, it will be much harder to track. In another month or so, the plant will turn brown and "melt" back into the ground, where it will remain dormant and be invisible until it emerges again next spring.

Fortunately, the homeowner promised to spray the plants in his yard. He also said he'd remove the plant from his sister's yard in the headwaters of the Eno River, where he planted some before realizing how invasive it can be. In speculating how it might have gotten into his yard, he remembered having gotten compost from the Durham landfill somewhere between five and ten years ago.

This means a visit to the Durham landfill compost site, long since closed, is in order, to see if there is an infestation there. Still to be determined is how to deal with all the plants that have already spread down the creek.