In the Weeds: A Guide for Maintaining Vegetation in Stormwater Treatment Systems in Rhode Island


In the Weeds: A Guide for Maintaining Vegetation in Stormwater Treatment Systems in Rhode Island is an illustrated guide of weedy and invasive plants known to invade and compromise the function of vegetated stormwater systems such as rain gardens, bioretention, bioswales, and tree filters. It is designed to help maintenance staff and supervisors identify problem plants in the field, and it targets the aggressive plants most likely to take over a stormwater treatment system in Rhode Island.

How To Use It

This guide is split into four categories: Trees, Shrubs, Herbaceous/Grasses, and Vines. Under each category, the plants are alphabetized by common name. When multiple plants have a shared name, they are listed by that name. For example, to find “Common Barberry” and “Japanese Barberry” look for the alphabetic placement of “Barberry.”

The photos illustrating each species were chosen to show different stages of the plant throughout the growing season. Because it is much easier to control invasive species through frequent inspection and weeding before they get firmly established, many photos show seedlings and young plants. Photos also emphasize distinctive plant features, such as large flowers, fruits, seedpods, and different bark textures.

An illustrated glossary of terms within the guide provides some explanation of botanical terms used.

For information on aquatic invasive species, visit:

Tips for effective weeding are also addressed in the guide.

Invasive vs. Native Plants

Each plant is labelled as either “Invasive” or “Native and weedy,” as this distinction may inform methods of control or removal. However, the majority of the plants listed in this guide are considered invasive. Many of them flourish in disturbed areas, such as newly-planted stormwater systems. There are also some native plants that are adept at rapidly colonizing disturbed areas, resulting in their overabundance. In this guide, the term “native” means that plants are native to Rhode Island, unless otherwise noted.

Learn more about invasive plant species.

See Acknowledgements and Resources for more resources and to go directly to the online sources of photos and information for In the Weeds