Over Christmas I could have written about holly or mistletoe, or maybe hellebores, but I’ve chosen the much maligned ivy. I know I’ve written about it before in terms of plants that gardeners hate, so I think it needs some support. I know some of you hate it and are dedicated to ripping it off walls, fences and the trunks of trees. You get frustrated that ordinary herbicides don’t kill it and you hate its ability to survive. But like any plant in a garden, in the right place and if the right variety is chosen it is wonderful. As one of the most enduring evergreens it has the advantage that it looks good throughout the year and really comes into its own in winter when so many of our beloved garden plants have given up the ghost.
The common ivy, Hedera helix is an amazing plant. It has the ability to thrive where little else will grow. It has colonised an unattractive fence at the end of our drive. Self-clinging stems of dark raven-green leaves moved steadily upwards, transforming the timber into a living wall. Now the plant is more mature woody stems reach outward, becoming greener and glossier in winter as the molecular flower heads develop. These are a valuable source of pollen and nectar for insects and later the berries are taken by birds. For me it is a source of wonderful foliage to cut for Christmas decoration. Even used in this way it lasts longer than other subjects.
On the bank, under a horse chestnut tree, which I should never have allowed to grow there, ivy has made a dark green carpet. No weeds grow in this space and the soil stays where it is meant to. Even when covered with a carpet of fallen horse chestnut leaves ivy never complains. Instead it grows through the leaves, enjoying its autumn mulch. How many other plants are this appreciative of rough treatment?
Ivy has gradually started to make its way up the trunk of the tree into the lower branches. I love it at this stage when it looks so determined. Of course it will eventually produce that adult growth becoming a bushy mass of shining green. A place for birds to roost and nest and a refuge for a variety of insects. It takes nothing from the tree but support. A young, healthy tree can lend that support willingly. It really only does damage when it is more vigorous than the tree itself and its weight becomes too much. As an evergreen it increases the wind resistance and this can be the downfall of an unstable tree.
Same thing with ivy on walls. If a wall is sound then the ivy aerial roots cling to the outside of the brickwork or render. If there are flaws in the structure the ivy may penetrate and damage. On fences the weight of the ivy can have the same effect as it has on an unstable tree. On a sound, sturdy fence it should cause no damage.
When it comes to the variegated cultivars of different types of ivy, no other evergreen climber can provide that amount of colour and interest throughout the year. Some are more vigorous than others and most make excellent ground cover. Hedera helix ‘Glacier’ is one of the best small-leaved ivies with silver green leaves edged and marbled with white. It is ideal for low walls and fences and superb as ground cover. I have a carpet of it under a pine tree, jewelled with white cyclamen in autumn and decorated with epimedium in spring. Again, no weeds and no unwanted soil movement.
I am particularly fond of Hedera helix ‘Green Ripple’, a dark green ivy with deeply cut leaves creating a rippled, textural effect. It is less vigorous than most and ideal to trails over walls and its great in pots. Wonderful for that container that you forget to water in a shady corner.
When it comes to large-leaved ivies Hedera colchica ‘Dentata Variegata’ is perhaps the finest for the small garden. Due to the strong variegation in the leaves it is slower growing than many hederas, and the foliage is healthy and weather resistant. The leaves are dark green and sage in the centre, broadly margined and marbled with rich cream. The effect is showy but subtle and works well on its own, or as a backdrop for other planting. This ivy will grow on any soil on any aspect. It grows slowly to 3 to 4 metres (10-13ft), but is easily kept in check by light pruning at any time of the year.
The alternative is Hedera algeriensis ‘Gloire de Marengo’ which used to be Hedera canariensis ‘Gloire de Marengo’. I knew it as this when it was widely sold as a house plant back in the late 60s. This has glossy leaves of soft and dark green edged and marbled with white. It will lighten and lift any dark wall or fence and makes wonderful ground cover.
If you want something even brighter to bring year-round sunshine to a shady spot choose Hedera colchica ‘Sulphur Heart’, a superb large-leaved ivy with dark green leaves boldly splashed in the centres with rich gold. It’s great for tree trunks and ground cover; I often plant it behind mahonia in a shady corner.
As you can probably tell, I’m an ivy supporter, and proud of it. If you sit in the other camp we still want to hear from you. Why don’t you like it? What has ivy ever done to you? After all its Christmas – maybe time to give it another chance.