A New Invasive in Town By Julie Sullivan GoNativeLI.com

From HOBAS Newsletter Article

If you’ve ever driven through the South you likely encountered miles of green mounds hiding trees, shrubs and even cars and structures. It is known as Kudzu — The Vine That Ate The South. Now imagine a vine just like Kudzu invading Long Island. It’s called Porcelain-berry, Ampelopsis brevipedunculata, and although prohibited from sale in New York State, it is exploding from existing plants in many of our backyards, parks and abandoned properties.

This vine was introduced to the US east coast from Asia/Siberia as an ornamental plant for its attractive berries, which ripen from green to white, pink, lavender, turquoise, and finally blue and black from late September through October. The leaves are often mistaken for grape leaves, but differ from them by their glossy undersides.

These invasive climbers, working their way through trees with their zigzag vines, are harmful to the ecosystem (the interaction between plants, animals and the environment), since they have no natural predators or diseases outside their homeland, aggressively out-competing native plants for water, nutrients and especially light. Consequently, once trees are hidden from sight, the bees, butterflies, and birds that evolved along with our native plants can no longer access their intended nutrient-rich food.

Porcelain-berry vines climb by their twining tendrils that are so tenacious they must be cut when anyone attempts to pull them from their supporting trees, shrubs, herbaceous plants, and even tall grasses. During the spring and summer, control these vines by hard-pruning, removing seedlings, and cutting and digging out established root crowns. Each crown supports an average of five vines above ground and several lateral, knotty roots, easily pulled out when cut or sawed at the crown. Once berries appear, remove and securely bag/dispose of them, including all berry-laden vines. Be sure to protect the native plants growing beneath, and because the vines hide multi-flora rose shrubs, wear leather work gloves — welding gloves are even better — and cut them at the ground.

Visit GoNativeLI.com/porcelain-berry to identify methods for removal.

And to see a recent infestation visit GoNativeLI.com/Restoration.

Lesser Celandine or Fig Buttercup It’s the last day of April and beautiful 9 petal bright yellow buttercup flowers cover lawns,  hill sides, stream banks, bogs and anyplace ground cover can grow.  Uprooting one of the multi-stem plants reveals the cluster of tubers that identify it as fig buttercup, also known as lesser celandine — a native European invasive to Long Island.

As with many of our invasives this plant is edible. The tubers, pulled before and after the flowers bloom can be boiled, roasted, and hot pickled. As with harvesting young invasive garlic mustard leaves, don’t be concerned about exhausting  the supply.

To slow the rapid growth of fig buttercup, start removing the plants as soon as they are identified. Hand pull plants before they set seeding structures. The stems of the heart shaped, wavy edged leaves, which may be solid green or with deep plum  blotches, can be easily grabbed at the ground, and gently yet firmly wiggled and slowly pulled to uproot the tubers. If the ground is compact use a  hand weeder garden tool. Then cook the tubers, following a recipe.

Garlic Mustard   The young sprouts of the first year’s growth remain relatively small throughout the growing season and don’t flower. In late April/early May of the second year the plant matures with small clusters of white flowers at the top of each stalk. Uproot and leave the small first year’s seedlings on site. Uproot and solarize all other stages, beginning with the flowering stage of this plant to prevent seedpods from developing and dispersing.

These flowering stems will continue to grow and produce seedpods — even if the entire plant is uprooted and composted or left on the ground and not destroyed. But first, because garlic mustard is edible, you may want to pinch off and cook the first year’s growth or the tender stems several inches below the young flowers in the plant’s second year.  Then uproot, solarize and dispose of the rest yard waste collection.

Collect a bag of the flowering stems with the tender leaves and even the seedpods for a delightfully pungent green vegetable side dish. Saute and prepare,  as for broccoli rabe. For a sweeter flavor, add orange or mango juice, cover, and steam for a minute. Garlic mustard also makes a tasty pesto.

Japanese Knotweed This shrublike plant can grow to over 10 feet tall. The stems are smooth, stout and swollen at joints where the six inch leaves meet the stem. Leaves are oval to somewhat triangular and pointed at the tip. In mid summer, small white sprays of flowers are followed by small winged  seeds.

Japanese knotweed seedlings are edible. According to Wildman Steve Brill, “You can eat Japanese knotweed shoots from mid-April to early May, before the plant gets tough and woody.”

Juvenile plants can be hand pulled and should be done routinely throughout the growing season. Use a pulaski axe to remove the larger plants, including all roots and rhizomes. The roots make a pleasant and healthy tea and are known to cure Lyme’s disease. Any portions of the root system not removed will potentially re-sprout. All plant parts and seeds should be bagged, solarized and disposed of prevent them from reestablishing.

Click here for more information about uprooting herbaceous plants.

Many of the trees we see growing on Long Island are highly invasive and non-native — commonly Chinese exotics brought here over 200 years ago. Today, most Long Island soils harbor viable seeds dispersed from their descendants via wind, birds, or mammals years to decades ago. Under the right circumstances — often sun exposure when land is cleared — these seeds will germinate and grow to out-compete native species.

Long Island’s invasive trees include the ubiquitous tree-of-heaven, Japanese angelica, Norway maple, and sycamore maple, plus some newcomers such as glossy buckthorn and Callery pear.  Tree Control will address removing small seedlings and saplings — defined as young trees four inches or less in diameter at breast height. Larger tree removal may require a town permit and  some trees may need treatment before cutting to prevent roots from sending out numerous sprouts.

Soon after removing tree seedlings and saplings, cover the open ground with mulch (a thick layer of leaves) or replace them with native, shade loving plants (plugs or seeds) such as white wood aster Eurybia divericata, and then mulch. This hardy, fast growing species is a beautiful shade loving weed suppressant. It self-seeds, blooms throughout September and is a source of nectar and pollen for native pollinators. Click Native Plants in Recent Posts:

Ailanthus altissima, tree-of-Heaven aka tree from hell, is very invasive. It is often confused in appearance with our native sumacs and black walnut. The trunk of tree-of-heaven is smooth (no ridges) and blotchy — resembling pig skin. However, the outstanding difference is the single “tooth” at the base on the otherwise smooth margin of the leaflets. Black walnut bark is deeply ridged and the leaflet margins are toothed.

The tree-of-heaven is dioecious — meaning trees are either male or female. Annually, the females can produce 300,000 or more wind dispersed seeds, which deposit on open ground and germinate by the hundreds or thousands in large patches for great distances downwind of the trees. The female can be recognized by the feathery-looking seed stems that remain at the crown of the tree through the fall, winter, and early spring after the seed pods (samaras) have dropped. Since the tree aggressively sprouts when cut, the trunk is often girdled to kill it a year or so prior to cutting down. Click Tree Control for ideas on removing seedlings/saplings.

Acer platanoides or Norway maple is similar in appearance to sugar maple. The easiest way to identify this tree is to break the leaf at the node where it joins the stem (petiole). You’ll notice white sap at the break, whereas saps from other maples are clear. Also, the point tips on Norway maple leaves have fine “hairs”, while the tips on other maple leaves are rounded.

The shallow roots of this species allow for simple removal of young trees and seedlings. See Tree Control.