Q: Shortly after we bought our house we got a new patio and raised beds along the perimeter of the garden. I had great dreams of planting lovely shrubs and flowers. However, I opted for climbing ivy to cover the bareness of the concrete walls of the garden. These plants are now totally overgrown and the trellises can barely be seen any more. I’ve noticed the roots of the ivy is starting to grow into the raised bed pavings, causing a big gap between them, so could cause the wall to be damaged too. How do I take down the ivy? Is it best to get rid and start from scratch again? G O’N
A: Like many gardeners, I have a love/hate relationship with this Jekyll and Hyde member of the plant kingdom, so I sympathise with your predicament.
On the one hand, ivy (or Hedera, to give it its proper Latin name) is a wonderfully resilient, versatile, supremely wildlife-friendly, drought-tolerant, long-lived evergreen climber that’s brilliant for covering a shady wall and/or hiding an ugly eyesore.
On the other, a mature ivy plant left unpruned will slowly, but surely, get out of control to the point where it can potentially cause structural damage to brickwork, stonework, wooden fencing and trelliswork as well as to water goods (drainpipes and gutters).
Part of the reason for this is ivy’s strange ability to metamorphose over the course of its life cycle from a climbing plant into a woody shrub. Like a hyperactive teenager, the juvenile form reaches for the sky, its long, slender, self-clinging shoots hauling themselves upwards by using their aerial roots to adhere to any nearby vertical surface (in your case, the walls of your garden).
But once the plant reaches maturity (typically after ten years), its growth habit changes dramatically. Instead of climbing, it begins to transform itself into a woody shrub capable of flowering and berrying with branches that thicken and spread outwards rather than upwards. Ironically, it’s at this later stage that it’s most friendly to wildlife, but most unfriendly to any built structures.
You don’t say how old your ivy plants are, but, judging by the photo, they look like variegated forms of the very vigorous, large-leafed Persian ivy (Hedera colchica) and/or Algerian ivy (Hedera algeriensis) that are in bad need of a hard prune, something they’ll cope with very well.
Use a sharp secateurs to do this, waiting until early spring (before the nesting season starts) to cut away any unwanted growth, especially any very top-heavy, shrubby stems that might eventually cause the plants to topple.
You mention that some of the plants’ roots are also starting to grow into the raised beds’ retaining walls, so you’ll also need to cut/dig these away to prevent further damage.
Then, carefully inspect your garden walls and any nearby buildings or garden structures to make sure that the plant’s stems haven’t grown through/penetrated any small gaps that they’ll forcibly widen with time. Remove any stems that threaten to do so. Regular pruning will help to keep these plants in shape, but you’ll always need to keep a watchful eye out to ensure that they aren’t quietly causing damage.
The alternative – a tough and tedious job – is to remove your ivy altogether and replace them with a selection of non-clinging species of climbers and wall-trained shrubs that don’t use aerial roots to support themselves.
Evergreen examples include Trachelospermum jasminoides, Osmanthus delavayi, Azara microphylla, holly (Ilex), Itea ilicifolia, Camellia and Ceanothus. If you decide to do this, then make sure to first thoroughly dig out the root systems of the ivy plants and to incorporate plenty of well-rotted garden manure and fresh top soil before replanting.
While you’re at it (budget-permitting), consider painting those garden walls dark grey to make them visually drop back and widening the very narrow raised beds running along the garden perimeter. Double their width (bear in mind that they don’t have to be raised) and you’ll be able to properly blur the boundaries of your garden and create the sort of lush, flower-filled border that you’ve always dreamed of.