Last Updated on September 17, 2022 by Plant Mom Care
The Holly (Ilex) is the sole genus of flowering plants with over 560 species in the Aquifoliaceae family. This species consists of evergreen trees, climbers, and shrubs, ranging from the tropics and temperate zones of Europe, Africa, and South-West Asia. This plant is famously used as Christmas decorations.
The genus was more widespread during the Tertiary period, with many species adapted to growing in laurel forests. These plants grow at sea level to higher than 6,000 feet with the high mountain species.
These plants are usually slow-growing, with some varieties growing to 82 feet tall. Plants grown indoors in pots generally reach 6 feet in height and as wide.
These plants have alternate green glossy leaves, often with spiny leaf margins, some species are attractively variegated with white or yellow along the leaf margins. The flower is an inconspicuous greenish-white of four petals. They are dioecious and need to be growing in the vicinity of each other for the flowers to be pollinated.
The small fruits of these plants, often called berries, contain a single seed. They vary in color from red to black to brown, in rare cases green or yellow.
Therefore the use of cut branches, particularly from the I. aquifolium variety, is widely utilized as Christmas decorations. The fruits are mildly poisonous for humans, causing diarrhea and vomiting if ingested.
However, these fruits are a good source of food in winter for birds, squirrels, deer, and small mammals who help in dispersing the seeds. Unfortunately, this has had a negative impact as well as the plant has quickly spread into native forests, thriving in the shade and crowding out native species.
Tropical species are particularly threatened by overexploitation and the destruction of their habitats by human activity. At least two varieties of this genus have recently become extinct and several others are under threat.
Holly Plant Light Requirements
This plant can either thrive under direct sunlight or partial shade, but it will still thrive in full shade. This adaptability makes it easy for these plants to grow in dense woodland.
When cultivated indoors, it needs diffused bright light, with adequate exposure to direct sun, particularly for the variegated species who might lose their variegation with insufficient light.
Holly Plant Watering
This plant is quite drought-tolerant. Water it well in summer every 2-3 days when the weather is hot. However, you must learn to judge how often to water as the soil has to be dry between watering since it cannot stand water stagnation. Reduce watering in autumn and winter when it only needs watering once every 3-4 weeks.
Mulching the base of the plant will help it retain water in summer and moderate soil temperature during winter.
Holly Plant Humidity
It prefers humidity to stay above 60%. Mist it frequently in summer every morning or keep a tray of wet gravel close by.
Holly Plant Temperature
This plant prefers temperatures around 70° F with a low temperature of 60°F. It will require more watering at higher temperatures. As long as it isn’t subjected to extreme variations of temperature, your plant will grow well. A hard frost will kill off entire branches, and high temperatures will cause leaf drop or leaf scorch.
Holly Plant Soil
This plant isn’t very particular regarding the type of soil it grows in provided that it drains well. It can even tolerate heavy clay or poor soil. Use a mix of regular soil and perlite for best results. Constantly wet soil will often cause root rot or other diseases.
Holly Plant Repotting
This plant’s roots are relatively shallow, so you don’t have to repot it often, perhaps once every 2 or 3 years. Prepare a pot filled with fresh soil and dig a big enough hole in the soil. Firmly grasp the plant’s base, gently lifting it to ease it out of its container and loosen the roots.
Quickly move it to the prepared pot, spread the roots, and then fill the hole with fresh soil. Ensure there’s good drainage in the new container. The container should allow for 2 or 3 years of growing before you upgrade sizes, meaning it should be 10 or more inches wider compared to the roots.
Water the plant well until water flows from the container’s base, adding more soil if necessary.
Holly Plant Propagation
Germinating the seeds of this plant is tedious and rather difficult, so reproduction by cuttings is a better choice. Prepare a pot filled with a mixture of soil and perlite. Take cuttings about 6 inches long in autumn, dig a hole as deep as the cutting and insert the cutting. Keep it at a temperature of 65°F and water it when the topsoil is dry. Rooting usually takes 40-80 days. It will take almost two years before it will need repotting.
One of the nice things about this plant is that it’s very easy to maintain once it’s established. Feed it every 2 weeks from April-September with liquid fertilizer with a lower concentration of nitrogen as excess nitrogen can damage the plant.
To properly maintain this plant and keep it compact (particularly indoors), you need to regularly prune it. Pruning the plant will prevent it from becoming gangly and scraggy.
Holly Plant Common Problems
This plant is very often affected by mealybugs, spider mites, whitefly, and aphids, particularly in conditions of low humidity. Perform frequent inspections for pest infestations and treat the plant with appropriate pesticides if pests are found.
Over-watering can make the plant susceptible to root rot. Follow the watering guidelines stated above to stop this from happening.
Spots on leaves can occur from fungal infections. Treat the infection with a suitable fungicide and remove all the infected leaves.