This plant erupted in my garden, about 6 weeks ago, almost under a large hydrangea and beside a 5 year old lilac tree/bush. It is currently about 8″ tall with the spiked head bending. It is a cool green. My friends thought it was lily of the valley before the flower head bloomed! The soil is good old North Toronto clay with lots of attempts to fertilize. It gets dappled sun most of the day only because of its position under the hydrangea. The garden is on the east side of our property.
The plant in your photo and description is Broad-leaved helleborine (Epipactis helleborine) an invasive species originating from Eurasia many years ago.
You can try to control it by digging out the plant before the flowers go to seed. However, the slightest bit of rhizome remaining will produce a new plant.
You can also try just cutting it down to the ground constantly to starve the plant. More information about Organic Weed Control can be found at:
https://torontomastergardeners.ca/wp-content/uploads/2012/07/Organic-Weed-Control.pdf
July 2, 2021