English ivy (Hedera helix)
The English ivy, or common ivy (Hedera helix) is the only evergreen climbing plant native to Central Europe and occurs naturally in oak and beech mixed forests, alluvial forests, on rocks, walls and in bushes. The aralia plant (Araliaceae) is a so-called self-climate – it can even hold on to smooth concrete walls.
Do you want to green your house wall with this robust climber? Then you should make sure that the facade is in good condition. If the plaster has permanently damp cracks, the plant tries to tap these water sources. The small adhesive roots form real roots in these places. They grow into the cracks and burst through their thickness growth over time the plaster. An intact ivy façade, on the other hand, lasts for a long time because the dense leaf wall protects the plaster from weather and temperature influences. Once the ivy has spread on the façade, it forms an important habitat for many warmth-loving insects and birds.
The ivy climbs up to 20 metres high, can live for more than 500 years and then forms trunks with a diameter of more than one metre. He climbs with the help of small adhesive roots that can anchor themselves to almost any surface. After planting, it initially grows rather sluggishly, after which annual shoots of up to one metre in length are possible, especially after pruning. Old plants suddenly form thicker and erect shoots that do not climb. This is the so-called age form. The bark of young shoots is initially green to brown-red, the bark of older twigs and branches is usually light grey.
The evergreen opposing leaves of ivy are very variable, which has contributed to the selection of numerous garden forms. The wild species has dark green, three to five times lobed leaves with strikingly bright veins. The leaves of the age-form are lobeless and diamond-shaped to heart-shaped. In addition, many varieties of common ivy turn slightly bronze, pink, red or dark red in late autumn at low temperatures. With some like the variety ‘Buttercup’ the autumn colouring shows up only on the underside of the leaves. The special feature here is that the plant simply turns its leaves in autumn so that the underside is on top.
The ivy bears inconspicuous green-yellow flowers arranged in small umbels. They appear only in September on the shoots of the age form and contain a lot of nectar. Because of its late flowering period, ivy is a very important source of food for honeybees and other insects.
The spherical black-blue fruits of ivy do not appear until spring after flowering, between February and April, and are slightly poisonous. They like to be eaten by blackbirds and other kinds of thrushes.
The ivy prefers absonnige to very shady, air-humid locations. In the sun it only grows in sufficiently humid soil, but frost damage caused by winter sun is the rule. Only the colourful foliage varieties like ‘Goldheart’ need two to three hours of sunshine a day to colour the leaves well.
This climbing shrub prefers humus- and nutrient-rich, calcareous subsoil, but is adaptable and grows even in dry, strongly rooted soil under birch trees. The soil should also be fresh to moist and alkaline, although the ivy also thrives on weakly acidic to acidic substrates.
Ivy is preferably planted in spring, so that the plants are well rooted by the first winter. In the first two years after planting there is usually not much happening, but after that the plants show a strong growth. To ensure that the climbing shrubs branch out well from the start, the shoots of a freshly planted ivy should be cut back by about half.
Young plants in unfavourable locations should be protected from the winter sun with a fleece. The removal of individual shoots or entire plants is very laborious, as the adhesive roots of the ivy are very difficult to remove. For solid masonry, this is best done by annealing with a gas burner and then scrubbing with a strong brush. Ivy grows much better on mulched soil than on bare, mineral soil. The plants do not need regular fertilization and also cope well with drought.
The common ivy belongs to the climbing plants that grow rapidly and climb up the facade in no time at all. In order to keep him in check, you can shorten long young shoots in spring and repeat this pruning measure in summer if necessary. You should redirect the flower shoots of the age form that protrude horizontally from the wall to side shoots. This gives you the dense shape and reduces the weight at the same time. The best time for this cut is in early spring, because later on ivy facades are popular nesting places for birds. In the case of ivy greened house walls, the windows must occasionally also be cut free with hedge trimmers.
Ivy grows even where most other species are not able to assert themselves, for example in the dense root network of Norway maple and birch. But the dominance also holds certain dangers, because most perennials and shrubs eventually strike the sails when they have to stand their ground against the ivy roots. Therefore only just as tough representatives can survive like cherry laurel, Funkie, Rodgersie or Waldgeißbart in its surroundings.
Ivy does not parasitize and does not choke the trees – these are myths – but only uses them as a climbing aid. Because ivy can climb up anywhere without climbing, like wild wine it is ideal for concealing unattractive building facades. However, he sometimes refuses to do his work on new concrete walls and white painted facades. The shoots turn away from bright, highly reflective surfaces because they cannot cope with the bright light. In botanical jargon this behavior is called negative phototaxis. A slightly darker coat usually solves the problem. Fresh concrete walls have a very high pH value, and ivy doesn’t like that either. It can therefore take a few years for his small roots to find support on such walls.
In the meantime, countless varieties of common ivy are available on the market, some of which, however, are not hardy and are therefore only recommended as room ferment. Especially specimens with white leaf parts are often only suitable for interiors or balcony boxes. Glacier’ and ‘Goldheart’ are two colourful foliage varieties that survive our winter undamaged. They should not be too shady so that the foliage is clearly coloured. Also in the growth-strength, the ivy-types differ. If you would like to green an entire house, you should choose strong breeds such as ‘Woerneri’ or ‘Lake Balaton’. For small areas or pots, dainty, slow-growing shapes are more suitable.
If you want to propagate ivy, it is best to do this with cuttings. The best time for this is in late summer. Cut off annual shoots so that they have two knots with leaves on them and remove the lower leaf. Place three such cuttings in a pot of growing soil so that the lower knot is well covered with soil. If you put a foil bag over the pot, the soil remains evenly moist until the shoots have formed roots after two months at the latest.
Diseases and pests
Various leaf spot diseases such as the Colletotrichum fungus or the Phyllosticta fungus can occur in ivy. In case of infestation, you should prune the plant back strongly and remove infected leaves. Since the spread of fungal diseases is promoted by a humid environment, it is also advisable to free the ivy from fallen autumn leaves. Furthermore, ivy – especially the variegated varieties – is susceptible to the bacterium Xanthomonas campestris pv. hederae, which causes ivy cancer. Typical symptoms are small, sharply defined spots on the edge of the leaves, which gradually spread to the leaves and, in the worst case, to the stems. Real control is not possible, but you can at least control the spread by removing the affected plants.
I am Don Burke, one of the authors at My Garden Guide. I am a horticulturist that cultivates, grows, and cares for plants, ranging from shrubs and fruits to flowers. I do it in my own garden and in my nursery. I show you how to take care of your garden and how to perform garden landscaping in an easy way, step by step.I am originally from Sydney and I wrote in local magazines. Later on, I have decided, more than two decades ago, to create my own blog. My area of specialization is related to orchid care, succulent care, and the study of the substrate and the soil. Therefore, you will see many articles dedicated to these disciplines. I also provide advice about how to improve the landscape design of your garden.