Invasive helleborine orchid spreads in yards

Orchids are generally picky about their growing conditions but not for broadleaf helleborine orchid (Epipactis helleborine). In the past few years, helleborine orchid, an introduced broadleaf perennial orchid from Europe has become a common weedy pest in many homeowners’ lawns, flower beds and in woodland areas of Brown County. Since its first discovery in New York in 1879, helleborine has spread extensively to other parts of U.S., including Wisconsin in 1930, because of intentional planting by gardeners.

Helleborine is fairly adaptable to many habitats but it prefers moist rich soil, in particular underneath a tree canopy. It has alternative leaves clasped to the stem, grows up to 3’ tall, and spreads by its aggressive rhizomes. It blooms in July and August with greenish color flowers tinged with purple. There some other color variations documented in helleborine, such as white and yellow with some purple tinges. The flower spike first emerges with a drooping blossom but later it erects upright.  Helleborine also reproduces by seeds.

Like any other invasive weed, helleborine is tough to control. Regular hand pulling or trimming it to the ground can weaken the plant and eventually might cause the plant to collapse. Alternatively you can try to control helleborine using an herbicide containing triclopyr as an active ingredient in lawns. You might have to repeat the applications, and it might take a few years to control the population.

For horticulture-related questions and advice, contact Brown County UW-Extension’s Horticulture Help Desk at 920-391-4615 or bc_uw_extension_horticulture@co.brown.wi.us.

Vijai Pandian is the horticultural agent/educator for the Brown County University of Wisconsin-Extension.