Hedera – English Ivy (H. helix)
Native to Europe, north Africa, and western Asia, Hedera (H. helix) is a genus that includes only a few species, but many varieties, of climbing or ground-creeping evergreen woody plants. The leaves of all types are leathery, and they are often lobed. A few of the hederas have large leaves, but most are prized for their dense, low growth, and small leaves. Most hederas produce short aerial roots from the nodes of stems and when they come in contact with any damp surface they attach themselves to it.
Hederas thoroughly deserve their reputation as decorative plants and have long been a basic feature of plant groups. They are useful as climbers, in hanging baskets, or as ground covers. Most of plants have stems that tend to branch naturally at frequent intervals making the plant dense and bushy. Some varieties of the species need to have their growing tips pinched out frequently.
H. canariensis Canary or Algerian ivy is a tall-growing species with triangular, slightly lobed leaves 5 inches (12 cm) long and 6 inches (15 cm) wide. The dark green leaves have fine, pale green veins and the stems and leaf stalks are deep red. H. canariensis ‘Variegata’ sometimes called H.c. ‘Gloire de Marengo’ has smaller, variegated leaves with patches of grey-green and bold creamy yellow margins. The leaves are 3 – 4 inches (7 – 10 cm) long and 2 – 3 inches (5 – 7 cm) wide.
H.h.English ivy has typically dark green ivy-shaped leaves with three to five lobes, of which the one at the apex is the longest and most pointed.
H.h. ‘Chicago Variegata’ has creamy-edged leaves 1 – 1½ inches (2.5 – 3 cm) long and 1½ inches (3 cm) wide. ‘Golden Chicago’ leaves are marked with golden yellow patches.
H.h. ‘Cristata’ commonly called Parsley ivy has 1½ – 2 inch (3 – 5 cm) long and 2 inch (5 cm) wide medium green leaves that are so notably undulate that they seem curly-edged.
H.h. ‘Glacier’ has medium green leaves with grey-green blotches, white marginal patches, and pink edges. Leaves are 1½ inches (3 cm) long and 1 inch (2.5 cm) wide. This plant needs pinching out two to three times a year to maintain dense bushy growth.
* Keep ivies away from children or pets. Compounds in English ivy are somewhat toxic and include glycosides that cause vomiting, diarrhoea, nervous conditions, and dermatitis in sensitive individuals.
In the outdoor garden, they are able to climb to at least 80 –100 feet (25 – 30 m) above the basal ground level on suitable damp surfaces such as walls, trees, and rock faces. In some areas of the world, Hederas have been designated as a noxious weed due to their tendency to threaten all vegetation levels of forested and open areas, growing along the ground as well as into the forest canopy.
Light Hederas need bright light. Variegated types need two to three hours of sunlight a day in order to retain their colour contrast. Green-leaved hederas do best if kept out-of-direct sunlight. Gaps between leaves lengthen and plants become spindly if light is inadequate. In summer, keep hederas out of direct sunlight or the leaves will burn.
Temperature Hederas do well in a wide variety of temperatures. In winter, encourage plants to take a short rest period by keeping them cool. Provide extra humidity if the room is warm.
Watering Water plants moderately when actively growing. Let the top ½ inch (1.2cm) of soil dry-out between waterings. Water sparingly during rest period.
Propagation These plants root easily by taking 3 – 4 inch (7 – 10 cm) cuttings and placing in a glass of room temperature water in bright indirect light. Plant in soil mixture when roots are 1 – 1½ inches (2.5 – 3 cm) long. Taking stem cuttings and placing in a moistened soil mixture enclosed in a plastic bag can also propagate Hederas. When the cuttings have rooted (2 – 3 weeks) remove the plastic, water moderately, and feed monthly with a standard liquid fertiliser.
Potting/re-potting. Re-pot when pale roots emerge through drainage holes.
Stems can also be cut back to the desired height and will produce new, compact growth. Stem cuttings can be used to start new plants. For the best effect, pot up four to six small plants.
Feeding Feed plants every two weeks except in the fall and winter when plants aren’t actively growing. Wash the leaves with warm water.
Leaves all green. Variegated types revert to all-green habit in shady conditions. Increase the light by placing close to a window or use artificial light if necessary.
Leaves undersized, bare spindly growth. Mature leaves tend to drop off at the stem base with age. Cut back bare stems. Check to see if the plant needs re-potting.
Red spider mites. Ivies are very susceptible to red spider mites if the room is too warm and the humidity is low. Spray the leaves with warm water once or twice a week, and put foliage under running water once a month.
If you do have an infestation, use a non-toxic pesticide (see recipe) to eradicate the problem. If you would prefer to purchase a product, insecticidal soap will take care of the mites. Follow manufacturer’s directions carefully.
Use a handful of soap flakes, ¼ tsp. (1 mL) vinegar, and 1 qt. (1L) water. Pour into a plant mister, only spray where needed.