Bottomland • Itadori begone • Understory conditions (P0.0)
This clearing is at the northern end of a long, low-lying area that runs north-south. It is hemmed in by a western slope bordered by Narragansett Parkway and a gentler eastern slope that merges with upland woods growing on glacial till.
The dense foliage overhead during the growing season and the damp soil contribute to the shady ambiance of a bottomland environment. Even on the hottest of summer days, this spot remains relatively cool. During the cold months, light passes unimpeded through the leafless canopy, and introduced species like crow garlic and Japanese honeysuckle are able to ramp up leaf production while native species are dormant.
Prior to the summer of 2020, Japanese knotweed, or Itadori as it is known in Japan, was the dominant species in the clearing. Removing the weedy jungle restored the bottomland habitat to several other species.
Unfortunately, Japanese knotweed readily sprouts replacement shoots from a robust root system after being cut. So, it will be necessary to diligently remove stems over a number of growing seasons to deplete the underground reserve of nutrients. Elsewhere, knotweed rhizomes have been measured to a depth of 10 feet and laterally for a distance of 23 feet.
What kind of plants would grow well here, in the absence of knotweed?
Plants that can tolerate damp soil and limited light.
Native species revealed in the area after clearing knotweed include jewelweed, sensitive fern, tall meadow-rue and white avens. All are species characteristic of moist and shady understory in New England forests.
Look around at the small trees in this clearing. They include European buckthorn, European privet, and green ash. How could mature plants be distinguished from saplings?
Mature plants produce flowers and fruits during the growing season. Juveniles only produce leaves year-round.
Large individuals of Norway maple provide dense shade in this clearing. Moreover, their shallow roots inhibit the growth of other plants. Compared to undergrowth in upland woods, there are not many saplings or shrubs growing beneath their crowns.
Look for the labeled Norway maple in the clearing. Study the bark and you will readily recognize others in the park. Audubon Trail will pass through a grove of many large Norway maples before emerging onto the top of Audubon Field.