Resources on Invasive Plants
What’s So Bad About Non-Native Invasive Plants?
The National Park Services defines an invasive species as a non-native species that causes harm to the environment, economy, or human, animal, or plant health.
Non-native invasive plants or “NNIs” thrive because they out-compete native species.
- They lack predators.
- They aren’t generally recognized by insects, aquatics or animals as a source of food.
- Invasive species often destroy habitat, affecting the ecosystem where other plants and animals naturally live.
It’s time to remove these invasives from your yard!
English ivy has spread into most parts of Sligo and Long Branch parklands. It’s an environmental scourge for many reasons. As a non-native, invasive plant, it has no predators keeping it in check, it alters the ecosystem, it out-competes native plants. It is one of the invasives that Weed Warriors spend a great amount of time and effort removing.
On the ground, English ivy crowds out native flowers, ferns, and tree seedlings that are literally the future of the woods. It harbors mosquitoes and sometimes rodents.
When ivy grows vertically, it creates berries, spreading seeds. It retains moisture, accelerating branch and trunk rot. It competes with trees and shrubs for nutrients and water. Its vines grow to be heavy and can bring down branches, girdle sap flow, and block light at the crown of the tree. English ivy will engulf and kill the tree or shrub it grows on.
Our area has lost mature trees to storms, age, and tree cutting for houses, driveways, parking lots, and commercial development. If we are to fight climate change effectively, we will need to value and protect our mature shade trees. We will need to replace the trees we have lost not with small ornamental trees but with large native keystone species – oaks and other eastern forest species – that grow tall enough to create a cooling canopy over homes and buildings. Such keystone trees support a wide variety of wildlife, keeping the ecosystem healthy.
Get rid of your ivy! You’ll save your trees, promote native plant diversity, and foster a healthy yard and forest. Thank you for helping to rid Sligo Creek parks of ivy!
closeup of ivy vines on tree trunk
Ivy berries showing changed plant leaf shape
A tree in trouble: choked by ivy
3 Steps to Cut Ivy from Trees
Late fall and winter is a great time to cut ivy from a tree. The recommended strategy is to cut vertical vines but not pull them off the tree, and to remove ivy covering the ground for a two foot swath around the base of the tree.
1. Use garden clippers, a handsaw, or a lopper to cut ivy from the bottom 2 feet around the entire trunk of the tree. The goal is to cut off all ivy vines from their source of nutrients in the soil so they will die.
On heavily infested trees with ivy vines thicker than an inch, you will need to carefully saw through the vine and gently ease it away from the bark. A screwdriver may be useful for freeing enough ivy from the bark to allow a cutting tool around the vine. Wear gloves and long sleeves to lessen the risk of touching any poison ivy present.
Once cut, leave ivy on the tree. Do not pull it off because that could pull bark off the tree. Cut ivy will gradually turn brown and blend in with the color of the tree bark.
2. Pull all ivy vines out of the ground around the base of the tree, making a two foot “life saver ring” around the tree. This will help slow regrowth of ivy on the tree. If the ivy is not dense, you can pull it from the soil with your hands, especially the day after it rains. If the ground is very hard and the vines keep breaking, wait until after a rain to remove the vines. The cleared space allows you to see any emerging ivy from roots you missed.
Arborists suggest laying a 2″ layer of leaf or wood chip mulch extending two-three feet around the tree to preserve moisture in the soil and keep lawn mowers from getting too close to the roots. Keep the mulch 3″ away from tree trunk to ensure air exchange for the bark, and so you can spot any ivy trying to re-infest the tree.
3. Check up on your tree through the seasons to be sure the ivy remains off the tree and pull any regrowth on the ground.
Source: treestewards.org/take-ivy-off-trees, created by the Biodiversity Project of Chicago
Above: useful tools for cutting ivy (top); cutting rather than pulling the vine (middle); cutting a two foot ivy-free area on the trunk and around the base of the tree (bottom).
Invasive Plants of Sligo Creek by Type
Shrubs
Click on the common name for a photo. The “More Info” links are being updated.
| Common Name | Scientific Name | Notes |
|---|---|---|
| Japanese Barberry | Berberis thunbergii | ♠ More Info |
| Bamboo | Phyllostachys aureosulcata | £ ♠ Several varieties. Yellow groove Phyllostachys aureosulcata is the most common. More Info |
| Bush Honeysuckle (Amur) | Lonicera maackii | ♠ |
| Japanese Holly | Ilex crenata | £ |
| Japanese Knotweed | Polygonum cuspidatum | Changed to Fallopia japonica, a name not yet widely used. |
| Multiflora Rose | Rosa multiflora | ♠ |
| Privet | Ligustrum spp. | £ ♠ Other privet species also; none are native. More Info |
| Autumn Olive | Elaeagnus umbellata | £ |
| Rose of Sharon | Hibiscus syriacus | ♠ |
| Wineberry | Rubus phoenicolasius | A native raspberry, unsimilar in appearance, occurs in Sligo. |
£ The plant is found in only a few areas, though it might be numerous there.
♠ Indicates the plant was listed by Dorothy Salisbury as present in Sligo in 1970, although she noted most as rare or infrequent. See the Salisbury List.
Vines
Click on the common name for a photo. The “More Info” links are being updated.
| Common Name | Scientific Name | Notes |
|---|---|---|
| Asian bittersweet | Celastrus orbiculatus | No native bittersweet is known to exist. More Info |
| Asian Clematis | Clematis paniculata | Native clematis also exists; see the Native Plant Inventory |
| English Ivy | Hedera helix | ♠ On ground and also in trees. |
| Japanese honeysuckle | Lonicera japonica | ♠ A native honeysuckle also exists; see the Native Plant Inventory. |
| Kudzu | Pueraria lobata | ♠ in about six sites. |
| Mile-a-Minute | Polygonum perfoliatum | |
| Porcelainberry | Ampelopsis brevipedunculata | Sligo has three species of similar-looking native Grape. |
| Wintercreeper Creeping Euonymus | Euonymus fortunei | ♠ |
| Wisteria | Wisteria sinensis | |
| Akebia | Akebia quinata | |
| Japanese Hop | Humulus japonicus | Found with mile-a-minute, west side of soccer field on north side of Dennis. Escape from cultivation. More Info |
♠ Indicates the plant was listed by Dorothy Salisbury as present in Sligo in 1970, although she noted most as rare or infrequent. See the Salisbury List.
Native vines include Poison Ivy, Grape, Greenbrier, and Virginia Creeper. We are saving these plants so as not to interfere with natural plant relationships. Please do not cut any vine unless you are a certified Weed Warrior and have approval to remove them!
Herbs and Ground Covers
Click on the common name for a photo. Look on invasives.org.
| Name | Scientific Name | Notes |
|---|---|---|
| Bull thistle | Cirsium vulgare | More Info |
| Canada thistle | Cirsium arvense | More Info |
| Beefsteak Plant | Perilla frutescens | £ ♠ |
| Garlic mustard | Alliaria petiolata | ♠ |
| Lesser celandine | Ranunculus ficaria | |
| Mugwort | Artemisia vulgaris | ♠ |
| Periwinkle | Vinca minor | ♠ |
| Stilt grass | Microstegium vimineum | |
| Bishop’s Weed Goutweed | Aegopodium podagraria | |
| Gill-over-the-ground | Glechoma hederacea | ♠ ♣ |
| Indian Strawberry | Duchesnea indica | ♠ ♣ |
| Yellow Archangel or Golden Dead Nettle | Lamium galeobdolon | More Info Known only in section 6 |
Garden Bulbs – In some places crocus, snowdrops,and Star-of-Bethlehem are appearing frequently in grass and in the woods. Liriope and day lilies are also present occasionally, but not enough to be considered invasive.
£ The plant is found in only a few areas, though it might be numerous there.
♠ Indicates the plant was listed by Dorothy Salisbury as present in Sligo in 1970, although she noted most as rare or infrequent. See the Salisbury List.
♣ Spreading from sun to lightly shaded woods. We are not attempting to rid the park of it.
Aquatic Plants
Click on the common name for a photo. The “More Info” links are being updated.
| Common Name | Scientific Name | Notes |
|---|---|---|
| Water Hyacinth | Eichhornia crassipes | * |
| Water Lettuce | Pistia stratioites | ♣ |
| Water Primrose | Jussiaea sp. | £ |
* About 200 plants found and removed by resident Dominic Quattrocchi from the upper pond at Forest Glen, July 2006.
♣ About 10 plants found and removed by resident Dominic Quattrocchi from the upper pond at Forest Glen, July 2006.
£ Discovered in 2005 in six stormwater ponds. Permanent removal not attempted.
Trees
Click on the common name for a photo. The “More Info” links are being updated.
| Common Name | Scientific Name | Notes |
|---|---|---|
| Tree of Heaven | Ailanthus altissima | ♠ Please report this tree to the RIP Coordinator. |
| Flowering Cherry | Prunus avium | Section 6. Several hybrids present. |
| Mimosa | Albizia julibrissin | ♠ |
| Norway Maple | Acer plantanoides | ♠ |
| Princess Tree | Paulownia tomentosa | ♠ £ |
| White Mulberry | Morus alba | ♠ Sligo has a native Red Mulberry, with much larger leaves. |
| Yellow Buckeye | Aesculus flava | |
| Siberian Elm | Ulmus pumila |
£ The plant is found in only a few areas, though it might be numerous there.
♠ Indicates the plant was listed by Dorothy Salisbury as present in Sligo in 1970, although she noted most as rare or infrequent. See the Salisbury List.
Scientific names based mainly on websites and Brown and Brown’s Woody Plants of Maryland, 1972. Compiled by Sally Gagne, April 2004; updated July 2005.