Invasive species out-compete native plants.

Sometimes plants entice us to enjoy them with an abundance of flowers, brilliant colors or sweet fragrances. They use these lures to keep us from noticing the stealthy way they overtake more subtle but productive native species.  Several examples of this invasive style of growth are showing up in wooded areas and back yards this time of year.

 Garlic mustard (Alliaria petiolate)

Originally introduced from parts of Europe and Asia for food and medicinal purposes in the mid-1800s, this flowering plant has become extensively invasive in most parts of the US. It appears in early spring in the undergrowth of woodlands, forests, along roadways and anywhere there is a bare, moist or dry open area. Its presence overtakes many native plants.

garlic mustard

Garlic Mustard

It is a biennial that takes 2 years to mature enough to produce flowers that provide seeds.  During its first year of growth seeds germinate while the low-growing plants develop rosettes of leaves that can be hard to identify as an invasive. Its distinguishing fragrance of garlic when the leaves are crushed makes it easy to identify. A stalk appears the second year with small, white 4-petaled flowers atop the stalk. By the end of May seed pods that are dark and 4-sided develop and may each contain 22 or more seeds. The plant dies back by the end of June and the seeds are dispersed by humans or wildlife. The two-year cycle of germination and seed production continues as the plant spreads into new areas. Some research suggests that garlic mustard prohibits the growth of other plants in nearby areas. Seeds can survive as long as 5 years in the soil.

Management requires long-term  persistence. Hand- pulling to remove roots before seeds develop can be effective for small infestations. Removing plants with flowers and/or seed heads should be bagged and disposed of in the trash,  not in wood piles or compost areas. Chemical control can be effective but must be repeated due to the presence of seeds surviving in the soil.

Honeysuckle (Lonicera spp.) 

Honeysuckle plants were likely introduced into North America as ornamentals from Asia beginning in the 1750s. Some varieties arrived through the 1800s, and as late as the mid-1900s some varieties were still sold for various purposes such as arboretum specimens, for soil erosion control and for wildlife cover and food. Some varieties are still sold in nursery centers in some states; they are all prohibited for sale in Connecticut. They have all escaped cultivation and the seeds are spread by birds and wildlife.

The Connecticut Invasive Plant Working Group lists 6 types of honeysuckle on the state’s list of invasive or potentially invasive non-native species. They include the vine Japanese honeysuckle (Lonicera japonica), and the shrubs Amur honeysuckle (L. maackii ), Morrow’s honeysuckle (L. morrowii), and Belle honeysuckle (L. x bella). These are all considered invasive. The two potentially invasive varieties include the shrubs Tatarian honeysuckle (L. tatarica) and Dwarf honeysuckle (L. xylosteum). Plants that appear on this list are prohibited from importation, movement, sale, purchase, transplanting, cultivation and distribution under CT General Statutes §22a-381d.

lonicera morrowii early spring buds

Morrow’s honeysuckle with flower buds in early spring

Honeysuckle shrubs are leggy, have an open form and range from 8-12 feet high. The vining variety can grow to 30 feet or more. Leaves typically are opposite, oblong and have smooth edges. The leaf upper and underside of some varieties are smooth, other varieties are hairy. Green berries appear in early spring. Small tubular flowers appear within the leaves in May and June and can be white, creamy, yellow or pink. Often several petals cluster to form a tube. If sliced open, stems on non-native varieties will have a brownish hollow center. Stems on native species will have a solid center. Depending on the species, berries can be orange to dark red and ripen in mid-summer until late fall.

lonicera morrowii

Morrow’s honeysuckle blooming

True to their classification, these plants can form populations that out-compete and suppress the growth of native species.  They can deplete the habitat of moisture, nutrients and sunlight. In addition, the nutrients in the berries of invasive species are lower than native varieties. This requires birds to spend time eating large amounts of less nutritious food and could affect their migration.

While honeysuckle population numbers are low in an area, hand removal of seedlings or young plants is best before berries ripen and birds begin to spread them while feeding. Controlled application of herbicides might be required for areas of large infestation. A biological control is not known.

Native deciduous plants such as chokeberry (Aronia ssp.), spicebush (Lindera benzoin) and dogwood  (Cornus ssp.) will all provide food and cover for wildlife as alternatives to honeysuckle.

 Winged Euonymus  Euonymus alatus

Burning bush (Euonymus alatus), also known as winged euonymus, was introduced in the 1860s from Asia as an ornamental landscape plant. It is used extensively along roadsides, in parks and residential plantings and to beautify industrial parks all along the east coast and southern areas of the US.

euonymus alata

Winged Euonymus

It is a multi-stemmed, branching shrub that usually grows 8-10 feet but when mature can grow to 20 ft. It is called “winged” because of the shape of its stems. Small, greenish flowers appear in spring, followed by a hard fruit which matures to a reddish purple in the fall. The leaves of the bush become a brilliant red, giving it the popular name “burning bush.”

It is on the Connecticut Invasive Plant Working Group list of invasive species but its sale is not prohibited. It produces hundreds of seeds annually which generate many seedlings under the parent plant as well as in areas removed from its parent, such as surrounding woodland areas and neighbors’ yards. It seeds are spread by wind and birds.

Its spread can be controlled manually, mechanically or chemically.

Jean Laughman

 

Springtime usually means long hours at the UConn Soil Testing Lab often keeping me there until 6 pm or later. Upon leaving one night I noticed a large creamy colored moving object in the lawn area in front of the lab. At first I thought maybe it was a dog but when it turned, I could see that it was a rather large eastern striped skunk. I am guessing it may be a male as they are reportedly larger than the female and this is really a good sized animal. He does not seem to mind me observing or photographing him although I must say, I have not ventured any closer than about 50 feet!

Easterm striped skunk looking for food

Easterm striped skunk looking for food

As expected, the skunk was digging up the grass in search of earthworms, grubs and other insects. They also eat fruit, grains, nuts, small animals, eggs and garbage. I thought I would find the ground all torn up the next day but there were just some shallow, cone-shaped holes. The lawn area here is somewhat sparse anyways so damage would probably be more noticeable on a lush, healthy lawn.

Skunk damage in lawns

Skunk damage in lawns

Eastern striped skunks are found throughout the U.S., except in the dry Southwest, and also in southern Canada. They are very adaptable creatures and are found both in urban and suburban settings. They prefer low bushy habitats.

They typically have one litter a year which averages 6 pups. I will keep an eye on for mom and any young’uns. Skunks are a member of the Mustelid family which also counts weasels, minks, martins, otters and fishers as members. While all these animals produce a strong-smelling liquid in their scent glands, only skunks can spray this liquid on perceived threats. While I have not attempted to verify this, apparently a perturbed skunk will stamp its feet and arch its tail over its back before spraying.

Dogs seem not to understand this and often get in the line of fire, including one of mine, years back. After shampooing her several times with dishwashing soap, the smell still lingered. My husband, at that time, thought some men’s cologne would cut the scent and to this day every time I smell this particular fragrance, I only think of skunk!

Whenever skunks or moles are found digging in the yard, many people’s first thoughts are to treat for grubs. We encourage folks to first find out whether or not they have a grub problem and then to treat it in the most efficacious way possible. Contact the horticulturists at the UConn Home & Garden Education Center for help on determining whether grubs are a problem and when the best time for treatment is.

Whether walking along side roads, biking or driving, one can’t help but notice the proliferation of wildflowers now in bloom – trilliums, wood anemones, bloodroot, bluets, dog-tooth violets and those pretty white flowers. Those pretty white flowers are an invasive species from Europe, garlic mustard. It may have been brought over to use as a food plant or for medicinal purposes.

Four petaled garlic mustard flowers with triangular leave on flower stalk.

Four petaled garlic mustard flowers with triangular leave on flower stalk.

Garlic mustard has rounded and toothed basal leaves but as the flower stalk emerges the leaves on it are toothed and triangular. The white flowers have four petals, like other mustard family relatives and are about a quarter inch in diameter.

The problem with garlic mustard, like many non-native plant species, is that it spreads rapidly in shady, moist habitats outcompeting our native plants. It does this several ways. First up to 7,900 seeds can be produced by a single plant! So, even if just a fraction of the seeds germinate and the seedlings survive, that is often enough to populate an area. In general, garlic mustard plants are biennial in growth habit. That means that seeds germinate and the plant grows vegetatively in year one followed in the second year by production of flowers and seeds. This tough plant begins second year growth almost as soon as the snow melts in March and April and it forms a decent size basal rosette of leaves which cover and shade out any nearby smaller and slower growing native plants.

Garlic mustard produces many flowers which result in many seeds.

Garlic mustard produces many flowers which result in many seeds.

Mature garlic mustard plants are believed to exude allelopathic chemicals which interfere or harm neighboring plants and also beneficial fungi that form symbiotic relations with our native plants. There is also a possible earthworm and garlic mustard connections. As non-native earthworms consume forest floor duff layers, they make these areas more amenable to the germination of garlic mustard seeds. It is also possible that increased earthworm activity may increase the soil pH slightly and since garlic mustard growth is retarded on extremely acidic soils, any increase would be to the benefit of garlic mustard. Another factor in its spread is that deer won’t eat this plant!

But garlic mustard can be consumed by us humans and frankly, the early young shoots are not that bad tossed into salads and stir fries. There are a number of recipes on-line. Do think about where you would be collecting them from as garlic mustard is an abundant roadside plant but soils in those areas could contain lead, gasoline and other contaminants.

If eating this invasive is not to your tastes, then consider starting a Garlic Mustard Challenge. This is a contest each spring to see which group of individuals can pull up the most garlic mustard plants. If you do notice garlic mustard on your property or in other areas that you care for, pull it up and bag it, flame it, dig it up, or spray it with an herbicide. This invasive species is doing much damage to our native plant populations and biodiversity in Connecticut.

Good gardening to you!

Dawn P.