Nonnative Ivies (Hedera spp.)

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Asteranae
Order	Apiales
Family	Araliaceae
Genus	Hedera

Scientific Name

Hedera helix

Common Name

English ivy

Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.

Plant

Evergreen woody vines climbing to 90 feet (28 m) by clinging aerial roots and trailing to form dense ground cover. Thick dark-green leaves with whitish veins and 3 to 5 pointed lobes when juvenile, colchis ivy with 3 slight tips and few sharp teeth. Maturing at about 10 years into erect plants or branches with unlobed leaves and terminal flower clusters that yield blackish-to-purplish berries. Hundreds of cultivars vary in leaf size and color. Caution: Fruit toxic to humans, and plant contact triggers dermatitis in sensitive individuals.

Stem

Woody slender vines when a ground cover and growing to 10 inches (25 cm) in diameter when climbing infested trees and rocks by many fine to stout aerial rootlets. Vines pale green (sometimes reddish tinged), rooting at nodes, becoming covered with gray-brown shiny bark, segmented by encircling and raised leaf scars, and roughened by tiny ridges. Bark light gray to brown, bumpy and gnarly, with aerial rootlets that exude a gluelike substance to tightly cling to vertical structures. Older vines sometimes grown together where crossed.

Leaves

Alternate, with shapes varying according to age—typical juvenile plants having 3 to 5 pointed lobes and mature plants broadly lanceolate (English and Atlantic) to cordate (colchis). English generally less than 3.3 inches (8 cm) wide, Atlantic up to 4 inches (10 cm) wide, and colchis about 4 or more inches (10 cm) wide. All thick and waxy, dark green (some whitish variegated cultivars) with light-green veins radiating from the petiole and pale green beneath. Colchis dull green above, drooping, and fragrant when crushed. Hairs whitish on English, yellowish brown to rusty brown on Atlantic, and scalelike on colchis (requires a hand lens). Petioles to 6 inches (15 cm) long and pale green.

Flowers

June to October. Terminal hairy-stemmed umbel clusters of small greenishyellow flowers on mature plants. Five thick and pointed petals, 0.1 inch (3 mm) long. Each petal radiating from a 5-sided domed green floral disk, 0.1 inch (3 mm) wide, tipped by a short pistil.

Fruit and seeds

October to May. Clusters of spherical drupes, 0.2 to 0.3 inch (7 to 8 mm). Pale green in late summer ripening to dark blue to black in late winter to spring.

Ecology

Thrive in moist open forests, but adaptable to a range of moisture and soil conditions, including rocky cliffs. Avoid wet areas. Shade tolerance allowing early growth under dense stands, but becoming adapted to higher light levels with maturity. Grow very aggressively once established. Amass on infested trees, decreasing vigor, and increasing chance of windthrow. Increased sunlight promotes flowering and fruiting. English serves as a reservoir for bacterial leaf scorch that infects oaks (Quercus spp.), elms (Ulmus spp.), and maples (Acer spp.). Spread by bird-dispersed seeds and colonization by trailing and climbing vines that root at nodes. Drupes mildly toxic, discouraging overconsumption by birds. Foliage consumed by some butterfly larvae. English rarely produces fertile seeds on the Gulf Coast.

Resembles

Resembles grape (Vitis spp.) which has a leaf that is similarly shaped but not thick and often hairy.

History and use

Introduced from England, Europe, and Asia in colonial times. Traditional ornamentals and still widely planted. English a source of varnish resin, dye, and tanning substances.

Distribution

English ivy found throughout the region with scattered dense infestations in every State. Especially frequent in urban forests. Currently Atlantic and colchis ivies only in NC and SC.

Management strategies

Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of plants and fruit in a dumpster or burn.
Treat when new plants are young to prevent seed formation.
Pull, cut, and treat when fruit are not present (take measures to avoid rashes that can develop from skin contact).
Repeated cutting and mowing to groundline commonly recommended for control of young infestations.

Recommended control procedures

Thoroughly wet all leaves (until runoff) with one of the following herbicides in water with a surfactant (July to October for successive years): Garlon 3A or Garlon 4 as a 3- to 5-percent solution (12 to 20 ounces per 3-gallon mix) or a glyphosate herbicide as a 4-percent solution (1 pint per 3-gallon mix). Use a string trimmer to reduce growth layers and injure leaves for improved herbicide uptake. Cut large vines and apply these herbicides to cut surfaces.
Or apply basal sprays of Garlon 4 as a 20-percent solution in a labeled basal oil product, vegetable oil, kerosene, or diesel fuel (where permitted) (5 pints per 3-gallon mix); or apply undiluted Pathfinder II to large vines, avoiding the bark of desirable trees.

Images

English Ivy: July	English Ivy: July	English Ivy: July	English Ivy: June
English Ivy: July	English Ivy: July	English Ivy: July	English Ivy: January

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