Is Ivy on Facade Okay?

Hedera helix ("English" ivy) from Europe does do damage. It roots along the vines so actually roots into mortar and grooves in cement.

In natural setting, this ability allows it to get some very sheer stone faces and make it in rather tough growing conditions where other plants might not succeed. The roots slowly adhere into even tiny fissures and help break up the stone face and create opening that allow other plant species to set up shop.

It also roots into tree bark so people take it off trees when it's young since it can slow tree growth, especially of concern on managed tree lots.

Parthenocissus comes from Asia and North America (although there may be natives species from other places...too tired to bother looking it up). The one we call "Boston" ivy is from East Asia and has solid, maple-like or grape-like leaves.

"Virginia creeper" really is a touch more aptly named and is our native "ivy". It is preferable to plant/encourage self-seeded plants of this variety with its "palmate" leaves. Sometimes the leave shape is more solid but it usually will have the palmate leaves.

Both parthenocissus climb with pads that set down on surfaces and stick. The pads do not root into mortar or cause particular or major damage like English ivy does. When taken down after years of growth, the pads tend to stick to hard surfaces which some people find unsightly. Once the vines are gone and the adhered pads have a couple of years of weathering, they usually breakdown.

If Boston ivy is growing up a stuccoed wall where the stucco surface is no longer well attached to the underlying masonry (or wood), the stucco may come down in pieces if someone pulls well-grown Boston ivy down in a rough many. It's best in this kind of situation to cut it down carefully and then work on small left over stems connected to the pads instead of yanking vines down wholesale.

Boston ivy seems to cover walls more thoroughly and aggressively than Virginia creeper which seems a bit shyer (but can be very large in certain settings). Put head to head, I would imagine Boston ivy will manage to cover a wall or structure in much less time than our native Virginia creeper.

No matter what, they don't damage walls particularly and have other important plusses:

1) shade sunny walls and overhang windows to reduce summer overheating while looking cute when viewed from indoors

2) feed birds with their berries and offer shelter from spring and summer storms and sometimes offer nesting locations...and as a roosting area, walls covered in Boston ivy or Virginia creeper offer a great bird socialising spot which can protect them from predators and heat while helping to create wildlife friendly backyards. A wall of ivy can act a bit like a tree for birds who are flying down to a feeder, birdbath or ground foraging.

3) AND often turns a blazing red/orange in fall, drops leaves and allows full sun to penetrate during winter.

Now, despite some of the problems with English ivy, it can be considered an asset once in a great while. Apparently, on heavy masonry (certain kinds of stone in particular) it can help reduce frost damage on sunny walls since it keeps its leaves throughout the winter and prevents sunny walls from going through the frost/warmth/frost cycle which causes damage and can speed up spalding and the like.

I like the English ivy on the ground as a general groundcover and growing a little bit up a tree we have because it gives us wintertime greenery to look out at and some cover for the soil and birds when there is no snow.

And I like the native "ivy" for walls.

One thing, on wooden buildings, you do have to watch out with the parthenocissus varieties because they can sometimes send delicate shoots between battens and boards so it ends up growing in places it may not be intended to grow.

You'd never want English ivy growing on most wood varieties because it does, indeed, break it down over a short period of time. It's good at rooting into and helping break up fallen trees in the forest so it is just as good on lumber!

Posted by: BrooklynGreene at May 21, 2009 6:38 PM