Ivy looks nice, and many people like its appearance on the side of a house. However, when it is allowed to grow in areas with plants, trees or shrubs, it can pose a serious health threat to those plants very quickly. It is not parasitic, but through its growth habits it can strangle the health and life out of those plants.
Ivy Growth Habits
Ivies are vining plants that grab onto whatever they can as they grow. Like all plants, they gather energy from the sun. Since they have the ability to climb, they will climb whatever is in their path. Buildings, fences, trees and plants—none of these things are obstacles for ivy.
Some ivies, such as the invasive species called English ivy, wind around the trees and plants that they climb. As the plants grow larger, they become strangled by the ivy that wound around them when they were smaller. As ivy grows bigger, its vines also grow thicker, furthering the choking of whatever it has grown around. It does not matter how large or small the plants, trees or shrubs are that the ivy climbs. Even huge redwood trees can have their ability to absorb nutrients severely compromised by ivy strangulation.
If invasive ivies are allowed to grow unchecked, they can thrust plants into constant shade. Ivies are resilient and can grow almost anywhere, under any conditions. They also have no natural predators. These two factors, when combined, make it very easy for them to prevent other plant life not only from getting nutrients but also from getting light and air. Ivies, in short, can prevent other plants from getting everything they need to survive.
Dealing with invasive ivy species is a long process that requires followup treatment. You should cut low, accessible portions of the vine away from trees and plants. Remaining pieces then can easily be removed. If remaining pieces are out of reach, they will shrivel up, die and fall away because they are no longer able to gain nutrition from their roots. To avoid large ivy problems, you should deal with ivy as soon as you notice its encroachment in your garden areas.
Plant life is not alone in being threatened by invasive ivy. While concerns about nutrient, water and light deprivation do not come into play, ivy growing on inorganic structures can pose other problems. It can pull gutters and utility conduits off a house if allowed to run rampant. Ivies have been encouraged for ornamental purposes, but if left unchecked they can do a lot of harm to gardens and homes alike.