Connecticut Invasive Plants: Bush Honeysuckle

Toni Leland

Bush Honeysuckle (Lonicera spp.) looks so pretty that it is hard to imagine that it is one of New England's most invasive species. As summer progresses, the fields and roadsides suddenly erupt with the beautiful yellow and white fragrant flowers that cover the long branches of this shrub.

 

Honeysuckles can grow to 12 feet tall and includes a number of varieties: Amur Honeysuckle, Morrow's Honeysuckle, Tatarian Honeysuckle, and Bell's Honeysuckle. These were all introduced into our landscape as ornamental plants and, apparently, they really like it here. They have been found in most environments, including wetlands.

 The plants begin to show foliage early in the spring and by summer have taken over wherever they are growing, including finding their way into our gardens. For seedlings and young plants, hand pull or cut to the ground. For mature shrubs with large bases, cut down and use a systemic herbicide on the stump. Always read and follow directions on any chemical label.

Connecticut On Watch for Invasive Spotted Lanternfly

Toni Leland

Connecticut has been invaded by an exotic insect that presents a serious threat to our orchards, forests, vineyards, and nurseries. The spotted lanternfly (Lycorma delicatula) is currently only identified in Fairfield County, but due to the danger posed by this insect, all of Connecticut is now quarantined by the Connecticut Agricultural Experiment Station (CAES). Additionally, several towns in Fairfield County are now regulated.

This means that no materials from a regulated area may be moved to anywhere else in the state.

Authorities are asking anyone seeing this insect in any life stage report it at once to CAES. It is estimated that it could spread across the entire state within two years.

Spotted lanternfly has no natural predators and feeds on about 60 genera of trees and plants, with the possibility that approximately 47% of Connecticut's forest trees are potential targets for this pest, as well as fruit trees and grape vines.

For complete information on spotted lanternfly, visit https://portal.ct.gov/DEEP/Forestry/Forest-Protection/Spotted-Lanternfly

Connecticut Invasive Plants: Tree of Heaven

 Toni Leland

The Tree of Heaven, aka Ailanthus altissima, is a strange name for a plant that smells like carrion and runs rampant through our landscape.

This nasty prolific tree grows so densely and so rapidly that native species are literally wiped out. The tree and all of its parts are toxic, and it secretes some of those toxins into the soil. It has no natural pests, but welcomes some of our most harmful invasive insects -- including the Spotted Lanternfly.

Tree of Heaven grows about three feet per year and produces hundreds of thousands of seeds; it also spreads via underground suckers. Viewed from a distance, the tree is quite lovely with its lacy leaves, tall stature, and red and yellow seed clusters. If you've ever had one of these trees near your property, you are quite well acquainted with the hundreds of little seedlings that suddenly appear in your lawn. And don't crush the leaves! The smell is revolting.

 

Once again, this species was introduced by horticulturists about 240 years ago as a beautiful shade tree, and now the tree is well-rooted in all but six states here in the U.S. Scientists have worked for years to find a defense against this tree, and recently a fungus was found that actually kills this tree. It is a fungus found in Pennsylvania, Ohio, and Virginia and is called Verticillium nonalfalfae and gives hope that Tree of Heaven will someday be controlled.

Another tree that is confusingly similar, but more of a native plant is Staghorn Sumac, or Rhus typhina. In the early months of the year, the plants look almost the same, but once the blooms begin, Sumac is easily distinguished from Tree of Heaven. Large upright dark red-brown blooms appear above the leaves of sumac. Though it is native to North America, it can be considered invasive in the sense that it spreads rapidly and can smother other vegetation.

Connecticut Invasive Plants: Japanese Knotweed

 

 Toni Leland

Travel along any of Connecticut's beautiful scenic highways and byways in early to late fall and you'll see huge patches of plants with large green leaves and feathery white flowers. This is the dreaded Japanese Knotweed aka Polygonum cuspidatum, and it is a serious problem across the state.

This fast spreading plant thrives in many environments, but does spectacularly well in full sun and along streams and roadsides. The stands of knotweed are large, the plants are tall, and they shade out the native plants that we want. Every year, local garden groups gather volunteers to go out and hack away at this menace, which is not an easy task.

One would think that just digging up this alien might be the answer, but it only encourages it; like many types of crabgrass, knotweed has underground rhizomes and if chopped up, the small bits left behind simply grown new plants.

Knotweed isn't usually a problem in our home gardens, but if you want to contribute to the environmental health of our state, check out the local extension office to see where you might volunteer in this war against the aliens.

 

Connecticut Invasive Plants: Oriental Bittersweet

 Toni Leland

Autumn is the time when we look forward to cooler weather, changing leaves, and shorter days. But Connecticut gardeners don't look forward to the massive patches of alien plants that seem to cover everything at this time of the year.

One of the most obnoxious such plants is Oriental Bittersweet aka Celastrus orbiculatus. The problem with bittersweet is that it is quite beautiful with its bright orange berries that appear in late fall, beckoning the crafters to use it in dried flower arrangements and wreaths. Every one of these berries will grow a new plant! The berries fall off easily both during wind, bodily disturbance, rain, and being picked and carried to another location. Birds love them and help to spread this nasty vine.

 

Why is bittersweet so bad? Because the vine can strangle a young tree in one or two years, and left for years, the vines climb to the top of our beautiful old oaks, maples, walnuts, and evergreens, eventually smothering them or even bringing them down with the extra weight.

The berries make it easy to identify at this time of year, but this sneaky plant will quickly spread everywhere with small bright green leaves that might go unnoticed. As the vine grows it grabs everything in its path, blending in and daring you to see it.

Unfortunately, it is extremely difficult to get rid of bittersweet because of the berries and the additional spread by underground roots. One way to distinguish the plant from others is by examining the roots, which will be bright orange.

 

Small invasions can be controlled with hand-pulling and diligence. Watch your trees carefully and remove any vines you find. For large areas of this plant, some chemical control may be needed along with the hand maintenance. Always read and follow the directions on the label of any chemical you use, and be sure to only use those recommended for a specific problem.

Art from Water Pollution

Connecticut artist Kat Owens makes a stunning statement with her beautiful hand-sewn murals using trash collected from our waterways.

The UCONN Master Gardener booth at the Haddam Neck Fair is hosting Owens' amazing murals to help visitors understand the serious pollution affecting our coastal waterways. 

Using hard-to-recycle debris picked up from the shoreline, Owens created panoramic murals of various species of shoreline life. The impact is sobering to see, knowing the harm that these materials cause to our creatures.

Visitors were amazed to learn that the murals were created from trash, children especially were enthusiastic to see all the discarded items that were used in the displays, and had fun identifying them.

The day's favorite murals were the large shark and the sea turtle. Smaller murals showed birds and other fish.

One large mural of an octopus was not created by Owens, but inspired by her work.

See this wonderful display at the fair through Monday, September 6, and also learn more about our environment and how you can contribute. Help preserve Monarch butterflies with the free milkweed seeds we have. Learn about several new pests arriving in Connecticut, and see photos of the invasive plants we are constantly fighting. Talk to a Master Gardener about your garden or problems you might be having. We are there to help!

Swallow-worts Saboutage the Monarch Butterfly

Toni Leland

Our world is full of imposters and jokers, and the plant community is no different.

Sneaking into pastures, urban areas, forests, and our own gardens, the highly invasive swallow-worts belong to the milkweed family (Apocynaceae) and, therefore, are attractive to Monarch butterflies.

Why is this a problem?

Black and pale swallow-wort are highly toxic to the Monarch caterpillar, but the female butterfly often can't differentiate between the swallow-wort and milkweed, especially if they are growing in the same area. She lays her eggs on the swallow-wort and as soon as the caterpillars hatch and begin to feed, they die. Swallow-worts are so toxic that livestock—including goats!—will not eat the plants. 

The black swallow-wort vine originated from the Mediterranean regions of France, Italy, Portugal, and Spain, while the pale swallow-wort comes from Ukraine and southeastern Russia. This is another instance of a plant being purposely introduced into North America in the late nineteenth century, with unfortunate consequences.

Identifying Black Swallow-wort

According to details from the University of Rhode Island Biocontrol Lab, Swallow-worts are perennial vining plants with dark green leaves. Black Swallow-wort (Vincetoxicum nigrum) produces dark violet flowers, and Pale Swallow-wort (Vincetoxicum rossicum) produces flowers that are pale pink. The plants have a strong root system and, in late summer, produce slim, light green seedpods.
 

Black Swallow-wort growing up the side of a house in town. ©Toni Leland

How do we control it?

For the homeowner who discovers swallow-wort on their property, there are only a couple of remedies. Early detection and removal are the best management practices for small scale invasions. Dig or pull every plant and place in a plastic bag for disposal. Do not compost! For large infestations, chemical control is most effective, according to the Plant Conservation Alliance Alien Plant Working Group. The link contains complete instructions on effective application of herbicides.

Biological Control?

The University of Rhode Island Biocontrol Lab made the first releases of the moth, Hypena opulenta, in 2017 in the states of Massachusetts and Rhode Island. The moth was discovered on research studies in Europe and Ukraine, and determined to be the most likely candidate for biocontrol of swallow-worts. As with all experimental biological control studies, time will tell.

Because the swallow-worts disperse seeds in the same way as milkweed, these invasive vines can suddenly appear in even the most well-tended gardens. If you have a pollinator garden, be sure to include plenty of milkweed to give our lovely Monarchs enough hosts to continue the generations. And patrol that garden for swallow-wort.
 

Monarch on Common Milkweed (Asclepias syriaca) ©Toni Leland

Monarch caterpillar on Common Milkweed ©Toni Leland