Tag Archive for invasive plants

Winter Review: are you invasive species savvy?

Winter is the ideal dream time for cold-climate gardeners, but it’s also a perfect time to review good gardening practices and increase your gardening knowledge. For this Winter Review we’ll examine invasive species.

February 23 to 28, 2014 is National Invasive Species Awareness Week. Since winter snow covers most of Connecticut and cold temperatures continue to keep most gardeners inside, now is a great time read 10 Ways To Observe National Invasive Species Awareness Week.

There are many ways to prevent spreading invasive plants and creatures that seriously impact native species:

  • cleaning hiking boots, waders, boats/trailers, off-road vehicles, and other equipment or gear on which an invasive seed, plant, or creature may hitch a ride;
  • not dumping aquariums or live bait into waterways – something I thought was a no-duh;
  • using hay, mulch, and soil designated weed-free;
  • and planting only non-invasive landscape plants.

But, there are other means by which invasive plants and creatures spread: seeds and plant pieces may hitch a ride on gardening and lawn mowing equipment; potentially invasive weeds and seeds may arrive in nursery plants; and gardeners can inadvertently transport potentially invasive species by sharing plants from yard to yard or region to region. Even firewood can hide invasive insects – are you aware of the Emerald Ash Borer-caused ban on moving wood from ash trees and firewood out of New Haven county?

To become invasive species savvy, gardeners, homeowners, landscape workers – in essence everyone – must know where to find solid, trustworthy information. In Connecticut, start with

For a plant to be listed as invasive in Connecticut, it must be non-native and harm the environment, human health or cause economic harm in minimally managed areas (woodlands, waterways, open spaces) through its ability to establish and rapidly grow in a wide variety of conditions, reproduce prolifically, disperse over wide areas by vegetative fragments and/or seeds, and lack the growth and reproductive controls evident in the plant’s native regions.

A few of Connecticut’s most prolific terrestrial invasive plants include


Oriental bittersweet (Celastrus orbiculatus), as young plants and roots above;



Japanese barberry (Berberis thunbergii) as young plants, above, and en-masse, below, in early spring;



and Japanese Stilt Grass (Microstegium vimineum) as it emerges in early summer …


and shortly before it goes to flower and seed.



Connecticut is also plagued by Autumn Olive (Elaegnus umbellata), Garlic Mustard (Alliaria petiolata), Japanese Knotweed (Polygonum (Falopia) cuspidatum), Multiflora Rose (Rosa multiflora), Burning Bush (Euonymus alatus), and multiple other trees, shrubs, annuals, perennials, grasses and aquatic plants.

The Invasive Plant Atlas of New England is another great resource for New Englanders. Those in other regions should research the invasive species information provided by their state.

Learning about invasive species is an ongoing process … after gardening for more than three decades, I’m still learning. Every region is different, but learning what is already determined to be invasive in your area is the FIRST STEP in becoming invasive species savvy.

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Learn about local invasive plants

Here’s an opportunity to gain some hands-on knowledge about invasive plants plaguing Connecticut.

Gillettes Castle Invasives flyerVisit Gillette Castle in East Haddam on the third Sunday of June, July, August, and September, to learn how to identify and manage invasive plants that are likely or may soon try to establish on your property.

Master Gardeners with the University of Connecticut Master Gardener Program will speak, help identify, and answer questions about locally prevalent invasive plants.

These free education sessions run from 11:00 am to 3:00 pm, with a nature walk along the trails at Gillette’s Castle at 1:00 pm (kids are welcome).

The woodlands around Gillette Castle make a great invasive plant training ground. One of the major invasives there is Chinese wisteria. Chinese wisteria was planted around the castle grounds as a decorative landscape vine years ago. But, as Chinese wisteria will do when left to its natural devices, it spread … and spread … and spread.

Most of the ornamental wisteria you see planted in Connecticut is Chinese wisteria and, left untended, will act the same – spread and spread. When Chinese wisteria’s large purple flowers are in bloom it’s pretty easy to identify where the vine has spread into trees along some of Connecticut’s highways. It aggressively send roots underground and vines above ground choking out and weighing down everything it comes into contact with.

If wisteria is a must have in your ornamental garden the preferable wisteria to the Chinese variety (Wisteria sinensis) is native American wisteria (Wisteria frutescens).

During the nature walks on each Sunday, attendees will see just how much Chinese wisteria has spread along some of the castle trails and learn about the active project to reduce the infestation of Chinese wisteria at Gillette Castle.

Meet at the Gillette Castle State Park Visitors Center at 11:00 am this Sunday, June 16 or the following Sundays of July 21, August 18, and/or September 22.

Questions? Call 203-208-6085 or email AliensatGilletteCastle@gmail.com.

Before attending one of these informational sessions, get a heads-up on the many invasive plants, shrubs and trees altering Connecticut’s landscape by wandering around the Connecticut Invasive Plant Working Group website. You’ll be better armed to absorb the information you’ll hear during your Gillette Castle visit.

Digiprove sealCopyright secured by Digiprove © 2013 Joene Hendry

Japanese Stilt Grass, a Prolific Invasive Plant in Connecticut

The transition area between our front lawn and adjacent woods is a ‘wild’ area filled with woodland grasses, ferns, and mosses – lovely and very low maintenance, until now.  Last July I identified Japanese stilt grass in a section about six to eight feet wide and long. Japanese stilt grass is a truly scary invasive that is overtaking roadside edges, drainage culverts, and wooded areas in my neighborhood and elsewhere in Connecticut.

Japanese stilt grass spreads by seeds and possibly resprouts from rootlets not completely removed when pulling the plant.

This is what Japanese stilt grass looks like now, at the end of May on my Connecticut property.


Here it is even closer.


It doesn’t appear to be troublesome at first. It looks unassuming in the foreground below.


It’s actually a rather attractive low-growing plant that holds a lime-green shade all summer long. But don’t be fooled by its mild-mannered look. Left alone it will fill in so thickly that native grasses and other plants will be smothered. In the same area it looked like this last August.


Normally, Japanese stilt grass germinates in June. This year it germinated in May. Normally Japanese stilt grass blooms in August. This year watch for it to begin blooming in July. One plant … one of these thin stalks of greenery … typically produces about 100 seeds. Seeds remain viable for about seven years. Do the math. One stalk can cause 100 more stalks any time during the next seven years.

It has, does, and will spread.

We followed advised control steps: weed whacked it before it began to bloom and let it dry and remain in place. Any raking disturbs underlying soil and brings seeds to the surface to sprout. We left the area alone till Autumn. No new plants showed up.  Then we spread wood chips harvested from some of the felled trees on our property.

This year the stilt grass is back, presumably from seeds that must be in the soil. There must have been some in the area in previous years that went unnoticed and seeded. I’m pulling as much of the stilt grass as possible without moving the wood chips aside. I don’t plan to let it get as thick as it was last year. Continued pulling will have to continue throughout the growing season.

Pulled plants should be placed in a container and sent away with the trash. Ideally, to be sure the plants are degraded fully, let them sit in a plastic bag in the hot sun for a few days before throwing the bag in the trash. Do not compost Japanese stilt grass. It is not clear that home composting gets hot enough to kill it off. Do not throw Japanese stilt grass into the woods thinking it will die off; it may regrow from rootlets.

If you find this plant in flower beds, do not ignore it. It will quickly become a major problem.  Read UConn’s Invasive Plant Worksheet for more information.

Garden thoughtfully …

Digiprove sealCopyright secured by Digiprove © 2012 Joene Hendry