FOCAAdmin  Aug.27.2018
Invasive vines

On July 15 the Friends participated in New York State’s Invasive Species Awareness Week by hosting a workshop on Invasive Species at the Keeper’s House.   Workshop leaders Diane Alden and Daria Gregg have participated in surveying the entire Westchester section of the Aqueduct trail, are Wildflower Guides at Teatown and have adopted sections of the Aqueduct near their homes where they have been working for many years to control invasive plants and to do restoration planting with native species.  Diane is an amateur naturalist and Daria is a Citizen Scientist at the NY Botanical Garden.  

Diane started out the workshop with a statement about invasive species and about the use and meaning of the terminology used.  She emphasized that all of us belong to one species: Homo sapiens. Some biologists are hesitant to use the terminology: “invasive species,” or “non-natives,” when referring to plants and animals, because of the political implications.  But Diane stated that she could not find any way around using the terminology, as long as it is made clear that this does not apply to human beings.  

Diane Alden and audience

Photos: Elisa Zazzera

Why are we concerned about non-native plants?

Our ecosystem is complicated; each part is intricately connected to the other; the soil, the fungi, the plants (flora), the fauna including insects, birds, mammals and all the rest have evolved together over the millennia and all are in a delicate balance.  Each organism has natural enemies which keep it in check and also has mutualistic relationships with many other species.  Severe problems occur when plants and animals which have not evolved together are introduced to the ecosystem; they often do not have any natural enemies to keep them in check, they do not provide ecosystem services to their fellow organisms and they overrun the environment, outcompeting and often destroying the native flora and fauna.  Our insects depend on the native plants that support them – some can only survive when they have access to those plants with which they evolved – such as the monarch butterfly and milkweed.  Our birds depend on specific insects and berries that provide the proper nutrition at just the right time to support egg growth, to support winter birds during the cold winter, and to support migrating birds with needed calories and fats.  

Some invasive species produce berries that the birds eat, but these berries provide the wrong nutrition at the wrong time; so the birds eat them because they taste good, but they are like junk food for them, bad for their health and using up digestive juices on the wrong food!   They are high in sugar and become ripe just at the time when the birds need high fat berries.  This is just one example of how invasive species harm their local environments.  There are so many other negative effects.  Here are just a few: besides crowding out the native species, some alter the pH of the soil, and some, such as garlic mustard exude a fungicide that destroys the beneficial mycorrhizal fungi upon which the plants and trees depend.  

The picture below shows the demonstration that had been prepared for the workshop participants.  Labeled specimens of invasive species that had been found along the Aqueduct Trail in Dobbs Ferry were lined up along with charts showing some of their detailed characteristics.

Educational posters at the Keeper's House

Photo: Elisa Zazzera

Diane and Daria took turns describing each one before taking the group on a scavenger hunt to find them and place temporary labels along the trail to help with the identification.  

Here is Daria in her red shoes starting this demonstration:  

Daria and Diane in front of posters

Photo: Elisa Zazzera

Diane demonstrated Porcelain berry vine which grows rampantly on the trail, covering trees, bushes and plants, eventually killing them.  

Diane with Japanese Knotweed

Photo: Elisa Zazzera

Daria demonstrated Japanese knotweed, which grows on the trail and along roadsides, crowding out everything else in its way.

Daria with Japanese Knotweed

Photo: Elisa Zazzera

This workshop focused on the need to understand how destructive invasive species are, on how to identify some of them and thus encourage and motivate attendees to get involved in managing them.  It also touched on the complex and intricate nature of the plant/insect/bird interactions and how critical native plants are to this web of life. A short but very informative handout on this subject was Doug Tallamy’s article in the New York State Conservationist, February 2018 which is available on line:

With this in mind, we wanted to point out some of the valuable native plants that can be found on the trail that are in need of protection.  Here is Diane extolling the virtues of the native Spice Bush. 

Diane showing native spicebush

Photo: Elisa Zazzera

With plant labels in hand, we began our hunt for the invasive plants along the trail and to work to learn how to identify them.  

Newly educated, visitors look for invasives

Photo: Diane Alden

Here are some members of the group, on our lovely trail with the river in the background, proud to have identified garlic mustard, the plant that exudes a fungicide, killing the beneficial mushrooms that support our trees.   We labeled the plant and then retrieved the label on the trip back.  

Garlic mustard

Photo: Diane Alden

One attendee, Steve, identified an Oriental Bittersweet vine, the berries not yet ripe.  Later in the season they will open up to reveal the orange berry inside.  But this one may not have a chance to ripen because Steve vowed to return to cut down the vine and save the bush along the trail.  

Steve identifies Oriental bittersweet

Photo: Diane Alden

Steve correctly identified and labeled Japanese knotweed lining the trail.  

Identifying Japanese Knotweed

Photo: Diane Alden

The now quite knowledgeable group returned from the walk, accompanied by Tim Lamorte, reporter from the local newspaper, the Enterprise, who attended the workshop and published two photographs about the event.  

Tim LaMorte and group

Photo: Elisa Zazzera

Workshop participants were given handouts to assist with identification of invasive plants and were encouraged to continue to learn how to identify them, with the idea that they might work to minimize or eliminate them on their own properties, possibly join local groups – such as the Hastings Vine squad, adopt a section of the Aqueduct as an Aqueduct Steward and even start their own stewardship groups.  Other opportunities include participating in the May 4 I Love My Park Day in 2019, contributing to the Friends of the Old Croton Aqueduct, which supports invasive management projects, etc.     
Daria provided a handout listing opportunities and resources.  Here it is along with some useful website links.  


  1. Your own yard:
    1. If you do your own yardwork: Start small. Identify the non-natives, then research if they are a problem.
    2. Slowly remove them, roots and all if possible. Replant the area with an appropriate native plant for your habitat. Disturb the soil as little as possible, because the soil is a seed reservoir for non-native plants.
    3. Become a backyard habitat for birds: there are many organizations (Audubon and World Wildlife Fed.) to help you.  Or for step by step directions, see:
  2. Or hire professional help. Here are some suggestions:
    1. PLANitWILD, Bring back Habitat Amanda Bailey, 315 752 6877
    2. Ecobeneficial, Kim Eierman at
    3. Native Landscapes LLC, 991 Rt. 22, Pawling, NY (845) 855-7050
    4. MVH Garden Designs; ask for Meg (914) 935-1352
  3. Join a local organization that works to remove invasive plants on the Old Croton Aqueduct (OCA)
    1. For those wanting to work in the Hastings area and surrounding communities, contact Hastings Vine Squad:   
    2. For those wanting to work elsewhere on the OCA, contact Haven as per above or Diane Alden for information.   
  4. Sources of Native Plants:
    1. Earthtones,, Woodbury, CT
    2. Rosedale Nursery, Hawthorne, NY, Rt. 9A/Saw Mill River Rd. (does not specialize in native plants, but has a large selection of natives because of close affiliation with the Native Plant Center at Westchester Community College.)
    3. Native Landscapes LLC, 991 Rt. 22, Pawling, NY (845) 855-7050
    4. Toadshade Nursery, in Frenchtown NJ (mail order and some pick up)
    5. Rarefind Nursery, Jackson, NJ,
    6. Catskill Native Nursery, 607 Samsonville Rd., Kerhonkson, NY, (845) 626-2758
    7. Michael’s Garden Gate Nursery, 146 N Bedford Rd, Mt. Kisco, (914) 666-3177 (not exclusively native, but well stocked with natives)
    8. Wild Things Rescue Nursery

    Management & Restoration companies:

  1. Trillium LLC contact at
  2. Suburban Natives LLC,, Croton On Hudson, NY