Watercress AKA Nasturtium officinale  

When I first saw this plant growing along the edges of Merrick Brook years ago. I thought "Oh wow, it's watercress!"  Now that I have been researching invasive plants for a while, I have to admit I was pretty disappointed to find this plant on the list of outlaws. It's Latin name Nasturtium officinale makes you wonder what they were thinking when they named it. Its flowers and foliage don't resemble those of a Nasturtium in the least.  They are distant cousins though, and both plants have that pleasant peppery taste when nibbled.  You often find the word officinale incorporated into part of a Latin name for a plant. It simply means it is a plant used in medicine herbalism or cookery.  Watercress, which is native to Eurasia, is one of the oldest known leafy vegetables to have been consumed by humans.  Now found in many locations across the globe, it was introduced to America in the 18th century.  

The plant is in the mustard family, and like others in that family, it is considered a cruciferous vegetable because the four petals of the flowers, which form in clusters, resemble a cross or crucifix.  If you look closely at the flowers of Garlic Mustard, as well as kale, turnips, broccoli, and radishes you will see the same flower formation.  All of these are considered cruciferous vegetables, and being so, they are quite healthy veggies to consume. I am going to insert a consumption warning here.  

If you are planning to eat watercress found in the wild, first of all, as with any plant you might be foraging, be certain you have the proper identification.  Also, in the case of watercress, be certain you are harvesting from an extremely clean water source.  Otherwise, the plant could contain giardia, a parasite that beavers are notorious for carrying.  Perhaps even worse, if the water has been contaminated by manure, you may ingest a parasite called liver fluke, and that doesn't sound at all pleasant!  

The peppery flavor of the plant is actually part of the plant's defense system.  It is caused by two compounds contained within the plant that combine whenever the plant is injured.  For all its attempts at self-defense though, that zippy flavor does not stop ducks, muskrats or deer from eating the leaves.  Those particular herbivores seem to have gourmet taste, and they are one of the contributing factors to the plant's redistribution and spread along our waterways. Watercress is also a prolific producer of seed, which is another means of its spread. Portions of the plant can also be dislodged and carried downstream during heavy water flow where they can take root and form new colonies.  

I have never seen an exceptionally large colony of this plant in Merrick brook, or in the Shetucket River, but this plant does have the capacity of creating a rapid growing blanket of greenery that floats on top of the water, crowding out native vegetation and many of the things that rely on native vegetation to survive.  A large enough mat can deplete the water of oxygen. If you have a large infestation of this plant, you should make an attempt at its control.  

HOW TO REMOVE

This plant can be hand pulled very carefully so as to capture the entire root system and prevent regrowth.  After being pulled it should be bagged and removed from the site.  It is fine to just deposit it in the trash.  

When writing about various invasive plants and including a "how to remove" section I decided to include all of the recommended options provided by reputable sources, so please don't shoot the messenger! I am not a big fan of using herbicides and putting them in direct contact with a body of water seems almost unconscionable, but there are instances when their use is the lesser of two evils, and there are herbicide mixtures designed specifically for aquatic use. If you are dealing with a particularly large infestation of watercress that is crowding out other plants and depleting the water of oxygen, you may want to try one of the aquatic herbicides

     Autumn Olive AKA Elaeagnus umbellate & Russian Olive      Elaeagnus augustifolia 

Autumn olive and Russian olive are both hardy branching shrubs that grow in a form that resembles bush honeysuckle.  All of these shrubs produce a profusion of berries. Bush honeysuckle, autumn and Russian olive are all considered invasive, but should you wish to identify them, an easy way to tell the "olive" shrubs apart from bush honeysuckle is to examine a branch.  The bush honeysuckle has leaves that grow in opposite fashion, directly across from each other along the stem.  Both the Russian Olive, native to Eastern Europe and Central Asia, and Autumn Olive, native to China, Japan and Korea, have leaves that grow in alternate fashion along their stems.  If you snip a stem or branch from any honeysuckle, you will find a tiny hole in the center of the branch.  The branch of a honeysuckle shrub has a very narrow hollow portion in the center.  

Russian Olive was introduced in the early 1900's and Autumn Olive a bit earlier around 1830. Both were imported for their value as a wildlife habitat, as well as for erosion control, and their ornamental appeal.  The two "olives", which are technically not olives at all, readily escaped cultivation.  At this point they have both been declared an invasive species over most of North America and Europe. Positive identification of which "olive" species you are dealing with does not really matter because elimination strategies for either plant are similar.  In fact, the plants themselves have more similarities than differences.  For the sake of accuracy though, you can tell the two apart most easily when the shrub is in either its flowering or fruiting stage.  Autumn Olive has white or creamy yellow flowers.  When the fruit is mature it is red with silvery speckles or scales on its skin.  The Russian Olive has brighter yellow flowers and a fruit that is more yellow orange with silver speckles when mature.  Other more subtle differences are in the shape of the leaves, with the leaves of Russian Olive narrower in form than those of the Autumn Olive.  Russian Olive foliage appears more silvery due to the fine fuzz like hairs on both the top and bottom sides of the leaves whereas Autumn Olive has fuzz primarily on the underside of the leaves.  Both of the shrubs have thorns but they are fewer in number on Autumn olives.  Both bear abundant fruit which is edible and nutritious for birds, wild animals and, when the fruit is fully ripened, people as well.  The fruit of either variety is usually fully ripened by October.  Autumn Olive fruit will be bright red with silvery specks.  It usually gets sweeter after a frost and it remains on the shrub through November.  The fruit of Russian olive may not have as desirable a flavor or texture.  If you intend to eat this fruit please be certain you have made a positive identification.  Do not confuse the plant with bush honeysuckle as that fruit considered toxic for human consumption.  If these plants provide such an abundant food source, why should we attempt to eliminate them?  The thing is with their rapid growth and prolific seed production they out-compete many native plants.  They also have the ability to increase the nitrogen level in the soil in their vicinity.  The increased nitrogen level benefits autumn or Russian olive, but other plants that are native to our region may not find all that nitrogen beneficial.  

HOW TO REMOVE

If you happen to have them, goats really like to forage this plant.  They also love Multiflora Rose, and a variety of other invasive species.  If you allow goats to consume Autumn or Russian Olive plants while adding other non-invasive forage options, eventually the alternative forage options will crowd out the Autumn or Russian Olive eliminating those invasive plants.  If you are not fortunate enough to own goats, hand pulling of small plants is recommended.  This is best done after a good soaking rain which softens the soil allowing the roots to be pulled more easily.  Try to remove the entire root system as this plant may regrow from fragments left behind.   Repeated cutting of shrubs will eventually deplete the root system, but you need to be vigilant, continually cutting back regrowth.

During their active growing season, especially during the later part of their growing season when the crown of the plant is passing nutrients back down to the roots, the shrub should be cut as low to the ground as possible.  Follow up with an herbicide application to the cut stump to prevent regrowth.  Triclopyr is the preferred herbicide to use to eliminate this plant.  It should be used in its undiluted form for the cut stump treatment.  Another method for herbicide application is to prune the shrub back to a lower level and use triclopyr as a foliar spray when the plant resprouts and has fully formed leaves.  The leaves are what take in the poison.  Cutting the plant back first allows for the use of less herbicide during foliar application and it also makes it easier to reach all parts of the plant with the spray.  Be sure to follow the dilution instructions and all other instructions on the product's container.  Always wear protective clothing, and spray herbicide on a calm day.  

 Invasive Plant Walk Talk & Cut at the Scotland Public Library

On August 30, 2025, our group of twelve or so joined up with Rose Hiskes and Dr. Charlotte Pyle of The Connecticut Invasive Plant Working Group to learn more about invasive plants and native plants as well.  The day was clear and absolutely perfect. As we hiked along the trail, I came to realize how enjoyable it was to meet with like-minded people all of whom were well informed about the impact invasive plants are having on our landscape.  Rose and Charlotte were especially knowledgeable, providing us with botanical terminology and various ways to detect some of the invasive species no matter the season.  In addition to the invasive plants, they pointed out some exceptional native specimens growing along the trail.  

The trail along the boardwalk at the library is a soothing and peaceful spot.  The boardwalk itself is truly special, definitely worthy of preservation, as the boards used in its construction were purchased years ago by town residents and inscribed with their names or names of their loved ones, past and present residents of our town.  Unfortunately, over the years, the entrance to the boardwalk became so overgrown that you might not even realize the trail existed. 

After our informative walk with Rose and Charlotte, and a wonderful lunch which included a variety of delicious pizzas, a generous donation from our town's nip fund, we returned to the trail armed with energy, clippers, and various brush cutting tools.  About two hours later our group amassed a huge pile of invasive bittersweet, multiflora rose, and burning bush branches. I am excited to report that the opening to the trail is now once again visible!

After posting various "Wanted Reward for Outlaw Plant Posters" for invasive plants linking to articles this website, I was asked "What exactly is the reward?"  I can now affirm there are numerous rewards.  The camaraderie of working together with people is probably the most important one.  There is also the reward of accomplishment you feel when you step back and see the impact your work has made.  Then there is the reward of acquired knowledge.  In addition, a little bit of exercise can also be kind of rewarding.  Depending on which side of 60 you fall on, you might feel a tad achy the following morning from stretching to cut vines and from pulling out roots, but even that actually feels pretty good.

We will be meeting again in the not-too-distant future.  Feel free to join us next time if you missed the opportunity the first time.  I will keep you posted as to the date on the Scotland Residents FB page.  At the next meeting there will be no limit to the number of participants.  Stay as long as you can.  You don't need arrive at the beginning or to stay to the end of the work period.  Any help you can offer will be greatly appreciated.  Let's work together and get this trail back into shape!