Photo: Thejoyofplants.co.uk, styling by Elize Eveleens, Klimprodukties
English ivy is the houseplant of the month of April 2021. It is popularly grown as a hanging basket plant for its trailing branches and evergreen usually maple-shaped leaves. There are plenty of varieties to try and it’s an easy plant to grow.
Learn more about it here:
English ivy (Hedera helix), also called European ivy, common ivy and just ivy, is rather unusual among houseplants, most of which are tropical in origin, in that it comes from temperate Europe and just into Asia, from Ireland and Portugal as far east as Iran and Turkey, so is adapted to moderately cold winters. Indeed, some cultivars, like ‘Thorndale’ are quite hardy, up to USDA zone 5 (AgCan zone 6) when used as a climber and will tolerate even more cold when grown as a groundcover. The average houseplant cultivar is much less hardy, though, and unlikely to survive outdoors beyond zone 7 or 8.
English ivy belongs to the Araliaceae or ginseng family. The genus Hedera contains about 12 to 15 species, all woody climbing or groundcover plants native to the Old World: Europe, Asia, northern Africa.
Both its botanical names come from ancient Greek: Hedera from khandánō “to grasp” and helix from elix meaning spiral, thus “the clinging plant that coils in spirals.”
In Greek mythology, ivy is the plant of Dionysus (Bacchus in Roman mythology), the god of wine and plant growth. An ivy wreath is the symbol of victory and human power, which is why Olympic Games winners were given crowns of ivy.
To the Celtic peoples of Europe, ivy symbolized fidelity (it won’t easily let go of something it’s attached itself to) and eternal life (because the plant is evergreen). Much of that symbolism is still felt today.
In the wild, English ivy starts its life as a creeping ground cover and can live in that form for years, even decades if there is no support to climb on, but generally soon finds a host tree (or rock surface) it can start to climb up, attaching itself via clinging aerial roots. It then becomes a woody climbing shrub. It can reach up to 100 feet (30 m) in height and an every wider spread if it continues to creep across the ground. At this stage in its life, which can last many decades, it is still a juvenile, with small, five-lobed leaves.
When the plant reaches maturity, usually high in the crown of a tree, it undergoes a radical change, producing thicker, non-clinging, outward-arching branches and larger, thicker, heart-shaped leaves, thus taking on a shrublike appearance. Only at this stage does it bloom, producing umbels of greenish-yellow flowers followed by small, round, purple-black berries. The berries are edible to birds, but slightly toxic to humans.
Indoors, English ivy never blooms and is grown strictly as a foliage plant. It is usually allowed to trail from its pot, but can also be trained up a trellis, grown over a topiary form and will even climb walls on its own when conditions are good.
In some parts of the world, notably in mild temperate climates such as the Pacific Northwest (Canada and the USA) and the American South, English ivy is considered invasive, as it can self-seed abundantly and may cloak and stifle the growth of native trees. Interestingly, studies show the truly invasive species is not English ivy (H. helix), which is only moderately invasive, but Irish ivy (H. hibernica), very similar in appearance, but with a honeylike scent when crushed.
Of course, most modern English ivy cultivars are weak climbers and unlikely to become invasive, but still, if there is a risk in your climate, do keep your ivy plant indoors where there is no risk it could cause problems.
Both Medicinal and Poisonous
The leaves of English ivy are considered toxic to both humans and pets, although poisonings are extremely rare because of their bitter, nauseating taste.
Ivy was once widely used medicinally for treating various ailments (coughs, bronchitis, inflammation, arthritis, etc.), but not so much these days, partly because it can cause severe skin irritation in some people.
An Air Cleaner
Research by NASA demonstrated that English ivy is a powerful air purifier, removing such toxins from the air as benzene, formaldehyde, toluene and xylene.
There are some 500 cultivars of English ivy, many with variegated leaves with white, yellow, gray or pale green edges or markings or with “golden” leaves. Some have smaller, deeply cut or variously lobed leaves and can look likearrowheads, fans or bird’s feet. Habits vary as well: varieties with long, trailing branches were once favored, but today, self-branching varieties (they produce secondary branches at most nodes rather than endlessly long, branchless stems) are preferred. Cuttings taken from mature specimens are sold as “shrub ivies” and give plants with a very univylike upright, bushy habit.
Some of the most popular varieties are:
H. helix ‘Anne Marie’: medium green variegated leaves with a creamy-white margin.
H. helix ‘Chicago’: long, trailing stems with dark green leaves.
H. helix ‘Congesta’: a shrub ivy with dark green leaves arranged along two sides of the stem.
H. helix ‘Curly Locks’: large, rounded curly leaves with rippled lobes.
H. helix ‘Duckfoot’: tiny plant with miniature duckfoot-shaped leaves.
H. helix ‘Emerald Gem’: pointed emerald-green leaves.
H. helix ‘Glacier’: the most popular variegated variety, small leaves variegated green, gray and white.
H. helix ‘Gold Child’: large leaves with bright creamy-yellow margins.
H. helix ’Gold Heart’: dark green leaves with a creamy-yellow center.
H. helix ‘Jubilee’: dense, variegated foliage that is dark green, gray and white.
H. helix ‘Kolibri’: highly variegated silvery-white leaves flecked with emerald.
H. helix ‘Little Diamond’: diamond-shaped foliage with a white edge.
H. helix ‘Manda Crested’: large curly green leaves.
H. helix ‘Needlepoint’: miniature ivy with tiny bird’s foot leaves.
H. helix ‘Shamrock’: miniature bird’s foot leaves; deeply cut, rounded lobes.
H. helix ‘Zebra’: long, trailing variety with large, cupped leaves marbled creamy white.
Two other ivy species are commonly grown indoors: Algerian ivy (H. algeriensis) and Canary Island ivy (H. canariensis). They are closely related and have much larger, shiny leaves with shallower lobes … when indeed Canary Island ivy has lobes at all: sometimes its leaves are simply heart-shaped. Again, variegated cultivars are more popular indoors than the species themselves.
Finally, there is also a hybrid relative. × Fatshedera lizei, called tree ivy, is a very unusual intergeneric plant resulting from a cross between English ivy (H. helix) and a large shrub with huge palmate leaves, Japanese aralia (Fatsia japonica). The resulting plant, with star-shaped leaves much like its Fatsia parent, although of smaller size, seems undecided as to whether it is an upright grower or a vine: it grows upright at first, but eventually flops unless you stake it. Again, variegated cultivars are more popular than the species itself with plain green leaves.
Any Ivy by Any Other Name…
The term “ivy” originally described only plants in the genus Hedera, like the English ivy, but eventually also became a synonym for “climbing plant.” As a result, other climbers that are in no way related to true ivies have picked up the name ivy. These include:
- Boston ivy (Parthenocissus tricuspidata): a deciduous hardy climber in the grape family.
- Devil’s ivy (Epipremun aureum): a popular trailing houseplant, also called pothos.
- Five-leaved ivy (Parthenocissus quinquefolia): a deciduous hardy climber in the grape family, better known as Virginia creeper.
- Kenilworth ivy (Cymbalaria muralis): a small creeping flowering plant often growing in rock and wall crevices.
- Grape ivy (Cissus rhombifolia): a climbing houseplant in the grape family.
- Ground ivy (Glechoma hederacea): a weedy creeping groundcover or trailing container plant.
- Poison ivy (Toxicodendron radicans): a climbing or creeping plant causing contact dermatitis.
- Swedish ivy (Plectranthus verticillatus, formerly P. australis): a houseplant in the mint family with creeping, trailing stems.
This well-known term refers to some of the United States oldest and most prestigious universities, renowned for their ivy-covered walls. However, the “ivy” in question is not always English ivy (Hedera helix), but rather often Boston ivy (Parthenocissus tricuspidata), a very different and unrelated plant (see above).
Caring for Ivy
English ivy is a fairly easy houseplant to grow and thrives under “average” indoor conditions.
Light: Give it moderate light, perhaps with morning sun, such as near an east or west window. It will even grow in fairly deep shade, such as near a north window. In a sunny spot, protect it from direct sun in the summer by moving it back from the window or drawing a sheer curtain. It grows beautifully under LED and fluorescent plant lights.
You can also put your indoor ivy outdoors for the summer. Just make sure to acclimate it slowly so the leaves don’t burn… and to put it in partial shade or shade, not full sun. Bring it back indoors before the first hard frost.
Watering: Water it by applying the golden rule of watering: water deeply, enough to moisten the entire root ball, then allow the soil to dry before watering again. The finger test is the best way to tell when it needs water (stick your finger in the potting mix: if it feels dry, water; if it doesn’t, don’t), but you can also learn to judge watering needs by lifting the pot to test its weight: if it feels lighter, it’s time to water.
Do note that, under most home conditions, ivy will dry out much more slowly in winter (even more so if you keep it cool to cold), when it puts on no new growth, than in spring and summer, so you’ll have to modify your watering habits accordingly
English ivy is most often grown in hanging baskets. If so, the easiest way to water it is to take the pot to the sink and soak it in tepid water for a few minutes, then let it drain.
Letting the plant wilt can cause leaves and even entire stems to dry up and die or kill the plant, so try to avoid it.
Temperature: English ivy adapts well to indoor temperatures, but clearly prefers cooler temperatures in winter. If you can, give it temperatures below 60˚F (15˚C) at that season. In fact, it will be perfectly happy in an unheated room as long as it remains just above freezing. If you can’t keep it cool in winter, at least keep the air humidity up to prevent spider mites.
Fertilizer: Fertilize lightly with the fertilizer of your choice during the spring through summer growing season. Since it is essentially dormant from fall through winter, no fertilizer is required at that season.
Atmospheric Humidity: Good humidity is important, especially during the winter. It positively thrives in high humidity, but will tolerate down to 40% humidity. Below that and it becomes very susceptible to spider mites.
Use a room humidifier or grow it over a pebble tray. Spraying the leaves with water, a popular but useless method of raising air humidity (it doesn’t raise the humidity for long enough to make any difference to the plant: read Horticultural Myth: Misting Your Houseplants for more information) does at least dissuade spider mites.
Pruning: Ivies adapt well to pruning … and that’s good, because they often need it. Don’t hesitate to clip back wayward branches at any time. For an overall trim to give the plant a denser habit, spring is best.
Repotting: Young ivy plants bought in a small pot may need to be potted up (moved into a larger pot) once or even twice in their first year, when they become top-heavy, root bound or dry out too rapidly. After that, every two years should be enough.
The best time to repot is in early spring, but anytime from spring through fall will also do. Repotting in winter, when the plant is dormant, is not ideal. Any commercial potting mix will be perfectly suitable.
Multiplication: Ivy is most readily multiplied by tip cuttings inserted into potting mix (no rooting hormone is necessary) and rooted under a clear plastic covering. It will also root in water, but don’t leave it too long in that medium or you risk losing it. Don’t hesitate to pinch the tip of the young plant to stimulate better branching.
Ivy can also be multiplied by layering (you can fix a creeping stem to the soil of a nearby pot) or even grafting. Indoor ivy is almost never grown from seed, as its cultivars don’t come true to type.
Spring and early summer are the best seasons for multiplication of any sort.
You can simply grow ivies in regular pots or hanging baskets and let them grow into an attractive trailing plant or let them grow on their own up a wall or pinch them to create a rounded dome of foliage. However, you can also train them onto forms for a special look.
For example, they can be trained to grow over a simple wire frame into a shape like a circle, heart or pyramid, either a frame you purchased readymade or one you made yourself from heavy-duty galvanized wire. Make sure to include sturdy legs on the bottom of your frame you can sink deep into the pot so it will stand solidly upright. You’ll need a long-stemmed variety (not one of the self-branching types). Just weave its stems around the frame and fix them with a twist tie if necessary.
You can also create an ivy topiary by growing one on a sphagnum moss-stuffed wire frame. (You can find one online, in a craft store and in some garden centers.) Ideally, you’d use a small-leafed cultivar, planting it at the base of the frame. As it grows, pin it to the frame with a hairpin or a piece of wire bent into a V shape and keep the moss moist so the stems root into it. (The upper part will dry out faster than the lower one, so an ivy topiary will always need a bit of surveillance.) Such topiaries need to be pruned frequently to maintain their shape.
Aside from over or under watering and possibly too much sun, English ivy’s main problem is spider mites (or red spider mites, Tetranychus urticae). The tiny arthropods seem to come out of nowhere in late fall or winter and literally take over the plant. You’ll see tiny flecks of “dust” that move, plus, when they are numerous, weblike netting forming on the leaves. They can quickly kill the plant by draining it of its sap.
You’ll have no problem with spider mites if you keep the plant cool and humid in the winter. Spider mites thrive when the plant is stressed by dry air and continuous heating, so the most logical prevention is to keep your ivy cool to cold and moist. Failing that, you may need to take the plant to the sink once a week and thoroughly rinse it in water. This knocks off the mites and sets back their proliferation. Read more on controlling spider mites in the article Controlling Spider Mites on your Houseplants.
English ivy is rarely bothered by diseases indoors and other pests, such as mealybugs, scale insects and aphids, while possible, are not that common, as ivies are no more susceptible to them than most other plants. So, just keep an eye out for them and be ready to react if they do show up.
Where to Find English Ivies
Pretty much every garden center sells English ivies in their houseplant section: most often a choice of several no-name varieties you’ll have a hard time putting a proper label on. Usually, they offer both hanging baskets ready for display and smaller plants in individual pots, much less expensive, that you can have the pleasure of growing to trailing status yourself.
Plant collectors have a huge range of possibilities (remember there are some 500 cultivars available!), but named varieties may be hard to locate locally. Look online for nurseries in your country that do offer named varieties.
And there you go! All you really need to know about growing the ever-so-popular English ivy. Try one yourself and see!
Do you have a passion for ivy? Why not join the American Ivy Society and share your experiences with others of your ilk.