Hedera helix

Hedera helix (common name: Common ivy) is a species of ivy native to the most part of Europe and Southwest Asia. It is an evergreen plant that will readily grow up to 20-30 metres if given suitable surfaces to climb on (be it a tree, a wall, a cliff, etc.); otherwise, it will simply grow as a ground cover.

Two forms exist of the plant: the climbing form, and the arborescent form. The former form is considered the juvenile form of the latter; however, ivies kept as houseplants rarely take the arborescent form.

Characteristics
Juvenile leaves are alternate, 4-8 cm long and five-lobbed. The plant flowers late in the summer through late fall in 3-5 cm in diameter umbels. The flowers are very rich in nectar; pollinated flowers give small black berries that are poisonous to humans but nutritive for birds, who get from them an important source of food when the fruits ripen in the late winter. Hedera helix and its parent species are toxic.

The adult form of the plant is arborescent and features a change in the shape of its leaves, that become longer and usually lose their lobes. The adult form is rarely seen in culture.

Fertilization
The best fertilizer for ivies are those containing much Nitrogen, as the plant's main feature is its leaves. It should be applied to soil only, every month during active growth.

Light
The English ivy is tolerant to a very broad range of light conditions. It will grow in shade or in full light. They will do just as fine with natural or artificial lighting.

Indoor-grown ivies enjoy summers spent outside; they, however, should not be put in full sun, for they are not adapted for such a strong light and will suffer from it; rather put it in a shadier area.

Pests and diseases
Ivies are not very disease prone and it is especially true for plants that are regularly washed. Spider mites are the most common pests for ivies, leaving tiny yellow speckles on older leaves, leaves that will, eventually, turn yellow. As the infestation develops, the stems and leaves will eventually start being covered by webs, leaves turn brown, shrivel and dry out; a very careful eye will notice tiny little black dots moving in the webs - the spider mites themselves. Several thorough washings will be necessary to sort this problem out. A more humid, cooler air will help make the environment much less hospitable for spider mites.

Potting
When the plant becomes top heavy, root bound, or dries out too rapidly, it is time to repot. Put ivies into slightly larger pots, just large enough to hold the roots. Over-potting, or use of too large a pot for the size of the root system, and inadequate pot drainage can lead to root rot. Use either plastic or clay pots, depending on your watering schedule. (Clay pots dry out faster!) Be sure there is an adequate number of drainage holes that are at least 1/4" in diameter.

Always transplant into moist soil. If you water your plants frequently, use a commercially available, soilless mix which drains and dries readily. If you like a heavier mix which needs watering less frequently, make your own by using 1 part commercially available sterilized topsoil, 1 part Canadian sphagnum peat moss and 1 part perlite. Heavy, water-logged soils result in poor plant growth and make the plants less resistant to insect attack. (Because of this, you again really ought to consider using a pot that allows drainage if you plan to keep ivy successfully.)

FOR BEST RESULTS WHILE REPOTTING YOUR IVY: After removing your plant from its old pot, you may begin to loosen the root ball using your fingers, so that the plant's roots are all freed up from each other, no longer being held in a pot-shaped dirt clod. Lightly cover holes in the bottom of the pot with screening, old nylon hosiery, or clay pot fragments - anything to prevent soil from washing out of the pot without hindering water movement. Next, place a small amount of fresh soil mix into the new pot, spread the roots out evenly, and continue to fill soil around the roots to just below the rim. Then water gently, until water drains out of the pot. Always soak clay pots first before adding plants; otherwise the dry, porous clay will act like a wick to draw moisture from the soil.

Washing
Washing ivies will effectively help keeping them away from the few pests and diseases they might suffer from. The best way to achieve so would be to dunk the foliage in a gallon of water, in which a few drops of dish washing detergent will have been added (a warm shower will do fine for younger and more delicate subjects). The detergent will block the pores of the potential insects and mites that may have attempted colonizing the plant; in any case, it will clean the foliage from dust that unavoidably tends to fall on leaves through time and leave the plant with a fresh and clean look.

Watering
Ivies should be watered thoroughly when the soil feels dry, but infrequently. When the plant's soil feels dry to the touch, gently add water to the the soil until the surface is totally (and evenly!) wet. After allowing all excess water to finish draining from the bottom of the pot, do not water the plant again until the soil is once again almost dry. Do not allow pots to stand continuously in water, as this will not keep the plant watered, and will only encourage root rot and welcome harmful pests to use the standing water as a breeding ground.

If you insist on giving your Ivy plant a readily available supply of water at all times, then use of an enclosed, glass watering bulb is encouraged. Do not use an open watering spike, as open, standing water welcomes harmful bugs. Glass is recommended over plastic when selecting your plant's watering globe, as many plastics contain manufacturing chemicals that could slowly leech out into the plant's soil over long-term use. While inserting the stem of your watering bulb into your plant's soil, do so with slowly and with greatly gentle care, so as to not damage any of the plant's roots. Try to always use the same hole made by the globe's stem each time you replace your bulb after refilling so there's no risk of new root damage. (Aqua-Globes have the kind of watering bulb design you're looking for.)

During humid seasons, expect to water your ivy less often, as it will retain moisture longer during these times. If the air is dry, to prevent the soil from drying too quickly raise the humidity surrounding the plants by grouping Ivy Pots together on a tray full of wet pebbles or perlite, but do not allow the ivies ever just to stand in pools of water. (The pebbles in the tray serve to keep the plants' pots on top of the water's surface rather than having the bottom of their pot submerged in a puddle.) For indoor plants, use of an air humidifier during the dry months can be very beneficial when used in a good, nearby proximity- not only for your Ivy plants, but for many other kinds of houseplants as well, and this especially goes for air plants!

In extreme heat, it is recommended that you lightly mist your plants' leaves with cool water every 12 hours or so, depending on the severity of the heat. This helps to cool off your plant's foliage and relieve it from the continuous heat-damage that may otherwise cause for leaves to wilt or limbs to droop.

Flowers
Flowers are rare, if not an impossible occurrence on indoor-grown plants. However, it will readily flower in the wild.

Root Propagation in Soil
Cut a length of ivy vine using a clean pair of pruning shears or a sharp knife. Cut the vine length into two or more pieces, with each piece having one or two leaves. Make each cut directly above a leaf, and trim the stem below the leaf to about one inch. Dip the end of each stem either in a powder or liquid solution of Rooting Hormone- this is something you'll most likely have to buy online or in-store.

Fill a planter with sand, (or even some kind of sand & soil mix), and poke holes in the sand for planting. Plant each powdered stem in a hole and then gently push the sand around the stem.

Water the sand well, and place the planter in a plastic bag to help retain moisture. Open the bag once a week to water when needed to keep it moist. The ivy twigs will begin to sprout, and shall be ready to replant in a permanent location usually within six to eight weeks. Follow the same instructions for potting that you'd use for potting any other established Ivy plant, such as described in the "Potting" section from previously.

Root Propagation in Water
Ivy plants are also easy to root in water. Trim off any bottom leaves from your cutting's stem so that the bottom will be long enough for your jar, and then place the cutting into the jar, being sure to leave it on a well-lit window sill. In a few weeks, you should start to see small roots growing in the water. (If wanted, one may use certain types of Root Hormone solution made specifically for only Root Propagation done purely in water.)

So, while rooting ivy plants in water can be remarkably easy, it is always better for the plant when rooted in a solid planting medium, as transplanting water-rooted cuttings to the soil is more difficult and the overall plant survival rates are lower. Some claim that transplanting difficulties can be avoided altogether if the jar of water is full of very loose gravel or pebbles for roots to anchor themselves between to create a Hydroponic setup, which, while very effective for growing herbs and cannabis, could never provide the longterm growing conditions that Ivy plants require.

Therefore, the best way for an Ivy cutting to have favorable odds of survival after being transplanted, is for it to be propagated in a pot of sandy soil to start with, rather than only starting the roots in water.

Culture warning
Hedera helix is considered an invasive species in a number of areas, such as Australia and the United States. It can grow to the point of choking other plants and create thick "ivy deserts", where no other plant can grow. There are even several areas where the sale of the plant is forbidden, such as Oregon and some parts of Australia.

List of cultivars
The species itself is usually no longer cultivated, as over 350 cultivars are available to replace it.