Orchids have the reputation of being the most desirable of plants, so it’s hard to imagine one that you wouldn’t want growing in your garden. But such is the case with Epipactis helleborine, commonly known as helleborine or broad-leaved helleborine. This terrestrial orchid is native to Eurasia but has been in North America since at least 1879 when it was recorded for the first time near Syracuse, New York. It’s range has spread to cover much of eastern Canada and the United States as well as West Coast states and British Columbia. It’s unknown whether the species was purposely imported or if plants or seeds arrived accidentally with other shipments.
Helleborine grows from a large tangle of fibrous roots, sending up one or more 10- to 40-inch-tall stems. It blooms in late summer (July/August), producing a terminal raceme holding 15 to 30 (or more) small flowers, clearly recognizable as orchids, each subtended by a small green bract. Flower color is variable but typically is greenish white to yellow, often flushed with pink, and with reddish brown markings. The fruit is an oval capsule stuffed with hundreds of minute seeds.
Unlike most of our native terrestrial orchids, helleborine is quite adaptable to a range of sites and soil conditions. Unfortunately this has allowed it to become invasive in many natural areas. It has been found in several places at the Arboretum, including the Beech (Fagus) Collection. Helleborine is reportedly difficult to kill with standard herbicides such as glyphosate. Like similarly enthusiastic spreading weeds such as quackgrass (Elymus repens) and Japanese knotweed (Polygonum cuspidatum)[pdf], helleborine readily grows new plants from any fragment of roots left in the soil; if manually removing plants, be thorough when digging out the root mass.
Nancy Rose, editor of Arnoldia