Ilex

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Ilex

Hollies
Genus:Ilex
Family:Aquifoliaceae
Type:Trees and shrubs
Propagation:Cuttings, grafting, seed
Pruning season:Any time but midsummer
Pruning tolerance:High
Transplant:Readily transplants
Pest issues:Leafminers are a problem on many species
Bloom season:Spring
Fruit season:Fall and winter
Pollination:Insect pollinated, a good nectar source

Holly (Ilex) is a genus of about 400 species of flowering plants in the family Aquifoliaceae, and the only genus in that family. They are shrubs and trees from 2-25 m tall, with a wide distribution in Asia, Europe, north Africa, and North and South America. Many species are quite attractive, and are a fixture in both formal and informal gardens. The evergreen species in particular are used for winter interest, but some of the deciduous species are equally useful for their heavy sets of bright berries.

Trunk and leaves of a variegated holly bush.

Holly berries are mildly toxic and will cause vomiting and/or diarrhea when ingested by people. However they are extremely important food for numerous species of birds, and also are eaten by other wild animals. In the fall and early winter the berries are hard and apparently unpalatable. After being frozen or frosted several times, the berries soften, and become edible. During winter storms, birds often take refuge in hollies, which provide shelter, protection from predators (by the spiny leaves), and food.

In many Western cultures, holly is a traditional Christmas decoration, used especially in wreaths. The wood is heavy, hard and white; one traditional use is for chess pieces, with holly for the white pieces, and ebony for the black. Other uses include turnery, inlay work and as firewood. Looms in the 1800s used holly for the spinning rod. Because holly is dense and can be sanded very smooth, the rod was less likely than other woods to snag threads being used to make cloth.

Several American holly species are also used to make various caffeine rich teas. The South American I. paraguariensis is used to make yerba mate, a common drink. Ilex guayusa is used both as a stimulant and as an admixture to the entheogenic tea ayahuasca; The leaves of I. guayusa have the highest caffeine content of any known plant. In Northern and Central America, Ilex vomitoria, Yaupon holly, was used by southeastern American Indians as a ceremonial stimulant and emetic known as the black drink. In China, the young leaf buds of Ilex kudingcha are process in a method similar to green tea to make a tisane called Ku Ding tea

Description

The leaves are simple, and can be either deciduous or evergreen depending on the species, and may be entire, finely toothed, or with widely-spaced, spine-tipped leaves. Hollies are mostly dioecious, with male and female flowers on different plants, with some exceptions. Pollination is mainly by bees and other insects. The fruit is a small berry, usually red when mature, with one to ten seeds.

Species

Pests and Diseases

Hollies (here, Ilex aquifolium) are dioecious: (above) shoot with flowers from male plant; (top right) male flower enlarged, showing stamens with pollen and reduced, sterile stigma; (below) shoot with flowers from female plant; (lower right) female flower enlarged, showing stigma and reduced, sterile stamens with no pollen.

Arthropod Pests

  • Black Citrus Aphid: Toxoptera aurantii
  • California red scale: Aonidiella aurantii
  • Oleander scale: Aspidiotus nerii
  • India Wax Scale: Ceroplastes ceriferus
  • Florida Wax Scale: Ceroplastes floridensis
  • Tea scale: Fiorinia theae
  • Greedy scale: Hemiberlesia rapax
  • Camellia Scale: Lepidosaphes camelliae
  • Oystershell scale: Lepidosaphes ulmi
  • Gloomy Scale: Melanaspis tenebricosa (on I. glabra)
  • White Peach Scale: Pseudaulcapsis pentagona
  • Black scale: Saissetia oleae
  • Euonymus Scale: Unaspis euonymi
  • Cottony Camellia Scale: Pulvinaria floccifera
  • Cottony Maple Leaf Scale: Pulvinaria acericola
  • Holly Pit Scale: Asterolecanium puteanum
  • Holly scale
  • Lecanium scale: Lecanium spp.
  • Nigra Scale: Parasaissetia nigra
  • Walnut Scale: Quadraspidiotus juglansregiae
  • Yaupon Psyllid
  • Two-lined Spittlebug
  • Striped Mealybug: Ferrisia sp.
  • Comstock Mealybug: Pseudococcus comstocki
  • Berry Midge: Asphondylia ilicicola: infests the berries, preventing coloring.
  • Holly Leaf Miner: Phytomyza ilicis: maggot yellowish white, adult a black fly, flying in early spring
  • American Holly Leaf Miner: Phytomyza ilicicola: mines slender.
  • Twig Pruner: Elaphidionoides villosus
  • Twig Girdler: Oncideres cingulata
  • Japanese Beetle: Popillia japonica
  • Black Blister Beetle
  • Potato Flea Beetle
  • Holly Looper: Thysanopyga intractata
  • Bud Moth: Rhopobota naevana ilicifolia in Pacific Northwest
  • Fall Webworm
  • Holly Bud Moth (Blackheaded Fireworm)
  • Southern Red Mite: Oligonichus ilicis

Pathogens

Other problems

References

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