The Most Desirable Undesirable

 

It’s May and the sweet, citrusy smell of honeysuckle blossoms fills the air. For many people around the country the honeysuckle smells are emanating from invasive Asian and European species that have come to dominate the native honeysuckles in the landscape in the past century and more. The honeysuckle genus, Lonicera, encompasses more than 180 species from around the world, of which about 20 are native to North America. The primary reason any of this matters to American gardeners is how the invasive species, once a welcome addition to the landscape, will overwhelm other plants given even a little leeway.

 

Besides the bush honeysuckles which dominate the understory in woodlands and arch their branches into the space of neighbors in the garden, there are the twining vines of the Japanese honeysuckle (Lonicera japonica), which make their way into absolutely everything, whether along the ground or into the canopies of trees, robbing their hosts of sunlight, water, and nutrients. Once the blooms are done, red or purple berries follow, which birds love to eat, making sure the plants spread everywhere the birds go. Honeysuckle bushes and vines can also readily spread by layering, which is to say that parts of them touching soil develop roots, creating a leapfrog effect of new plants. Cut one section down to the ground, and likely as not another new plant has already started a few feet away.

Archilochus colubris - by jeffreyw - 003
A ruby-throated hummingbird (Archilochus colubris) sips nectar from a North American trumpet honeysuckle (Lonicera sempervirens). Photo by jeffreyw.

There are a number of other aggressive plants which have less to recommend them than the honeysuckles. English ivy (Hedera helix), for instance, offers no sweet fragrance or much in the way of bird food. Misguided people encourage it to grow on buildings, when what they would be better off planting is Boston ivy (Parthenicissus tricuspidata), a better behaved climber which won’t invade the mortar on brick structures, corroding it and pulling it out. Wild grape (Vitis spp.) has only found cultivated use in contributing genetic material to vineyard varieties. No one plants wild grape itself. It is mostly found in woodlands and has no ornamental value, though of course that is in the eye of the beholder.

 

2016-05-29 17 05 34 Honeysuckle blooming along Franklin Farm Road in the Franklin Farm section of Oak Hill, Fairfax County, Virginia
Japanese honeysuckle blooming along Franklin Farm Road in the Franklin Farm section of Oak Hill, Fairfax County, Virginia. Photo by Famartin. The blooms turn from white when they first open to yellow as they age.

Japanese honeysuckle and the bush honeysuckles are here to stay – there’s no eradicating such successful invaders who are popular with the native fauna, if not flora – and coping with them therefore becomes a state of mind as much as physical labor. Step outside in May and inhale the intoxicating scent of their flowers and observe butterflies and hummingbirds helping themselves to the nectar, and in summer take your ease in the shade or indoors while the berries form, knowing birds are noting their ripening until fall when they will descend on the plants and devour the berries, spreading new plants far and wide. It’s too hot and bothersome in summer to get after the honeysuckle with implements of destruction, but in winter when it’s cool and memories of their pleasant attributes are far away, get after those suckers and yank ’em out root and branch. Don’t worry – you’ll likely never get rid of them altogether, and come spring there will be a new birth of honeysuckle and with it a wonderfully sweet scent in the May air.
— Izzy

 

Walls of Ivy

 

The middle of winter is time for garden maintenance projects the growing season doesn’t allow time for, such as keeping English Ivy (Hedera helix) at bay by pulling it off trees and structures, or yanking it out of the ground. The idea of eradicating it altogether is best left to fantasy. Besides, some gardeners, like the ones who brought the plant from the Old World to the New in the Eighteenth Century, harbor no ill will toward English Ivy and instead choose to encourage it’s growth. Those who look on it as a pest and choose to discourage it can be left wondering why anyone in their right mind would plant it next to a building and allow it to destructively sink its roots into crevices in mortar or siding.

 

Hadera helix 1
English Ivy in winter climbing a tree in Poland; photo by Agnieszka Kwiecień.

 

The misconception about ivy’s destructiveness is due to confusion about names, and presents a good argument for learning the scientific names of plants rather than relying on common names. English Ivy, the invasive pest which produces aerial rootlets that find their way into a building’s cracks as it climbs upward, is not to be confused with Boston Ivy (Parthenocissus tricuspidata), which uses suckers to adhere to a building and is therefore less harmful. Boston Ivy is also an introduction from the Old World to the New, though it has a native relative in the Virginia Creeper (Parthenocissus quinquefolia). Boston Ivy, not English Ivy, is the vine that decorates old brick buildings around New England, and particularly on college campuses, where it lends its name to the Ivy League.
Boston ivy (Parthenocissus tricuspidata)
Boston Ivy in autumn, South campus, State University of NY at Buffalo; photo by Y.G. Lulat.

 

It is no easy or safe task pulling English Ivy off a building where some ill-advised previous gardener had planted it or allowed it to grow under the impression that he or she was evoking some of the atmosphere of tweedy academia. Depending on the building construction and its soundness, chunks of mortar or shards of wood siding are apt to come loose with the ivy where its rootlets have dug in. It’s best to cut the vines at ground level and let them die back in place, drying and shrinking in the process, and then after several months have passed, pulling away the remaining dried bits once they have lost their hold on the structure.
Wrigley Field-Right Field Ivy and Bleachers
Wrigley Field, Chicago – Right Field Wall with Boston Ivy; photo by Flickr user wallyg.
Some gardeners think they can manage English Ivy clambering on a well maintained building. They may believe its evergreen and tough-as-nails attributes are worth the trade-off of constant vigilance over the safer alternative of planting the deciduous and better behaved Boston Ivy. More power to them if they think they can keep an eye on it! It is far more likely, however, that where you see English Ivy on a building it is there because someone didn’t know any better and, relying on common names, thought one ivy wasn’t much different than another and so let it go thinking it lent the place a touch of classy greenery. An excellent case can be made here for paying attention to scientific names for plants rather than dismissing them as the affectations of pedantic know-it-alls, and it’s a lesson those gardeners have learned all too well who have spent countless winter hours tugging out skeins of Hedera helix where it has tangled itself into absolutely everything.
― Izzy