The fact that English ivy plants spread quickly means that they could be useful as ground covers for filling in hard-to-plant spots in your landscaping. Their aggressive nature suggests that they could be effective allies against erosion on hillsides. But they also come with a number of problems, so research them carefully before deciding to grow them.
Botany, Plant Characteristics, Growing Needs
Botanically speaking, English ivy plants are evergreen perennials. They are also classified as woody vines. Plant taxonomy refers to them as Hedera helix. English ivy plants can act as ground covers, spreading horizontally and reaching 8 inches in height. But they are also climbers, due to their aerial rootlets, which allow them to climb to heights of 50 feet or more. They will eventually bear insignificant greenish flowers but are grown primarily for their evergreen leaves. In this regard, they can be classified as foliage plants, as can another popular ground cover: Pachysandra.
Care, Uses, Warnings, Removal of English Ivy Plants
Their ability to grow in shade has made English ivy plants a traditional ground cover for planting under trees. Such areas in your landscaping can be extremely problematic, as most grasses will not grow well there. Vigorous, with a dense growth habit, this ground cover can be effective where the object is to crowd out weeds.
Some take advantage of the climbing ability of these vines to use them to cover a wall. They scale a wall by means of holdfasts, which are aerial-root-like structures. As you can well imagine with a name like "holdfasts," this feature has the potential to result in damage to a wall when removing the vines from it. Growing such vines on walls may or may not be a good idea, depending on the composition of the wall, your ability (and willingness) to repair the wall as needed, etc.
Their holdfasts also allow them to grow on trees. Homeowners often wonder if English ivy can harm trees. The fact is, any vigorous vine can hurt a tree because the leaves of a vine growing in a tree's canopy will block sunlight that would otherwise be used by the tree's leaves in photosynthesis. The added weight from vines is also an unnecessary burden on any tree with stability issues.
If English ivy is already climbing one of your trees and you wish to remove it, be careful. Do not just rip a vine off, which could hurt the tree's bark. Instead, cut each vine where you find it coming out of the soil at the base of the tree, where it begins its ascent. Cut off from the earth (and thus from a water source), the part of the vine left anchored in the tree bark will eventually wither and die.
This removal technique is the best way to get rid of the plant organically, but it does require some patience. You will need to go back year after year and cut new growth until, finally, all strength has been sapped out of the plant. It is only at this point that new shoots will stop emerging every spring. This is a method commonly used to eradicate another problematic vine, Oriental bittersweet.
The damage they cause to trees and to walls is not the only reason that H. helix vines have fallen out of favor in many circles in North America. As is often the case, aggressive growth is a double-edged sword, allowing you to cover bare spots quickly but at the price of invasiveness. They are considered particularly invasive in the Pacific Northwest. Moreover, these vines are poisonous plants for humans, for dogs, for cats, and for livestock. In other cases, homeowners simply want ground covers that, unlike English ivy vines, have pretty flowers.
Some homeowners grow these plants in hanging baskets, letting them cascade over the sides. Indeed, considering their invasive quality, the latter is a very sensible way in which to grow the vines for their beauty without having to worry that they will spread out of control.
English Ivy Plants in History, Culture
In the Christmas carol, "The Holly and The Ivy," we see a symbolism with these two evergreen plants that derives from pagan times. While the Druids thought of holly as masculine and suggestive of a male deity, English ivy plants for them represented female divinity.
In the ancient Greco-Roman world, ivy was sacred to the god, Dionysus (Bacchus in Latin).