Invasive Plant or Animal Research

English Ivy, Hedera helix L.

Ginseng family (Araliaceae)

Native Range: Europe, western Asia, and northern Africa 

One of the most popular ground covers in North America, English Ivy, this non-native climbing vine was introduced by early European colonists. Its vigorous growth creates an “ivy desert” as it chokes out other plants on the ground, and it poses a threat to both buildings and trees as it grows up vertical surfaces. The plant is reported as invasive throughout the Mid-Atlantic Region, including Alexandria and Arlington, Virginia, and also currently identified in the Four Mile Run stream corridor.

Identification Tips

• Woody, evergreen, perennial vine, trailing or climbing
  
• Leaves on non-flowering stems (juvenile stage): dull green, lobed, with distinct light veins; stems produce roots at nodes; most common leaf type on plant
• Leaves on flowering stems (mature stage): glossy green, unlobed; stems produce umbrella-like clusters of greenish flowers, followed by dark berry-like fruits
• Ivy plants can have both juvenile and mature stems
• Vines typically grow 90 feet long with stems up to one foot in diameter; can grow up 300-foot trees

Juvenile ivy leaves are dull green and deeply lobed, with distinct light veins.

Mature ivy stems have fuller, glossy, unlobed leaves and produce clusters of black fruit

Ivy is an aggressive climber and can topple or severely impact the growth of trees

Habitat in the United States

• Woodlands
• Forest edges
• Fields
• Hedgerows
• Coastal areas
• Salt marsh edges
• Other upland areas
• Where some soil moisture is present
• It does not grow well in extremely wet conditions
• Tolerates a wide range of soil pH but prefers slightly acid (pH=6.5)
• Often associated with some form of land disturbance, either human-caused or natural
  

English ivy has been reported to be invasive in natural areas in 18 states and the District of Columbia

Invasive Characteristics

Pros

• Provides shelter for wildlife (although this might also be seen as a con)
• Practically no maintenance in terms of watering and fertilizing
• Acts as ground cover to areas that have slow or stopped growth
• Ability to grow indoors and outdoors, can be transferred between seasons

Cons

• Slows and stops the growth of native plants
• Prevents sunlight from reaching surround plants because of dense leaf growth
• Makes its way past your siding and roofing
• Weight of the vine on the tree can result in an unbalanced structure, causing the tree to fall during severe weather
• Serves as a bacterial host that infects oak, elm and maple leaves
• Prevents tree from receiving adequate sunlight
• Can negatively affect circulation, smothering the tree
• Dense mats of ivy on the ground hide puddles and soggy soil, allowing mosquitoes to breed.
• English ivy carries Bacterial Leaf Scorch (Xylella fastidiosa), a plant pathogen harmful to elms, oaks, maples, & other native plants.

 

Ivy growing on the tree in Photo will eventually overwhelm this whole tree if it is not removed soon.

 

MANAGEMENT OPTIONS

Manual, mechanical and chemical control methods are all effective in removing and killing English ivy.

Manual and Mechanical:

For ivy growing on the ground, the most effective control method is pulling or digging out plants and removing the roots. Fall to spring is usually the best time for this because the ground is moist. Vines may reroot if left on soil, so pile them root-side up or discard them with yard waste. Since sap can cause a reaction in some people, gloves and long sleeves are recommended.

For ivy growing in trees, the key is separating the climbing vines from their roots. Ivy can only grow from roots in soil. (It doesn’t get nutrients from tree trunks). Cut and remove all vines to a comfortable height around the tree trunk. This will kill the upper vines; the lower vines will need to be pried off the tree and pulled out of the ground.

 

Chemical:

Foliar treatment is difficult due to the waxy coating on ivy leaves. Use of a surfactant will improve results. Combining glyphosate and triclopyr is more effective than either herbicide alone. The best time for herbicide application on ivy seems to be late summer, although results vary. Repeat treatment may be needed. Winter spraying can reduce damage to dormant native plants. Leaves are susceptible when they first appear, so early spring treatment or cutting followed by treating fresh regrowth can also work.

Cut-stem application with triclopyr or glyphosate is another effective method. Apply herbicide directly to freshly cut surfaces of living rooted stems using a spray bottle, sponge, or brush. Amount of active ingredient varies by product, so consult the label to find out what concentration to use for the cut-stem method. For more information, contact the Noxious Weed Control Program.

 

Alternatives to English Ivy

Many native plants are available to plant instead of English ivy.

For groundcover replacement:

• blue phlox (Phlox divaricata)
• wild ginger (Asarum canadense)
• green and gold (Chrysogonum virginianum)
• Christmas fern (Polystichum acrostichoides)
• northern maidenhair fern (Adiantum pedatum)
• northern lady fern (Athyrium filix-femina) 

For vine replacement:

• trumpet creeper (Campsis radicans)
• Virginia creeper (Parthenocissus quinquefolia)
• passionflower vine (Passiflora lutea)
• moonseed (Menispermum canadense)
• crossvine (Bignonia capreolata)
• virgin’s bower (Clematis virginiana)

 

 

 

Sources:

Master Gardeners of Northern Virginia at the Fairlington Community Center, Arlington Virginia, https://mgnv.org/

The Department of Conservation and Recreation (DCR), https://www.dcr.virginia.gov/

Arlington County, Virginia, https://www.arlingtonva.us/

Center for Invasive Species and Ecosystem Health, a joint project of University of Georgia - Center for Invasive Species and Ecosystem Health, USDA Animal and Plant Health Inspection Service, USDA Forest Service, USDA Identification Technology Program, and USDA National Institute of Food and Agriculture, https://www.invasive.org/