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Ilex glabra: Grow & Care for Inkberry Holly

Written by Iris

Aug 06 2021

Ilex glabra: Grow & Care for Inkberry Holly
Ilex glabra (Inkberry Holly) is a native compact shrub in the Aquifoliaceae that maintains leaves all year round. Ilex glabra (Inkberry Holly) is a relatively slow-growing species that can grow up to 5-8 feet tall. Ilex glabra (Inkberry Holly)  sometimes forms clusters with many buds, making it an excellent plant for low hedges or borders. The leaves of Ilex glabra (Inkberry Holly) are evergreen and toothed, reaching up to 2.5 inches. They are dark green and shiny on top and lighter and darker on the bottom.

How to Grow Ilex glabra (Inkberry Holly)

Steps for Ilex glabra (Inkberry Holly) Propagation with Seeds

Each holly berry each contains about four seeds. Growing holly from seed can be difficult as the seed germination is slow, requiring anywhere from sixteen months to three years. In addition, it can take another three years before the holly shrubs produce any flowers. A specialized coating to survive harsh winters protects holly seeds; however, this pulp-like substance also makes propagation more difficult. Nonetheless, growing holly shrubs from seed propagation can be done, with patience. Collect holly berries and break the skin off. Rinse the seeds in cold water and then plant them in soilless potting medium within a large flat. Cover the flats and place outdoors in a protected area over the winter. If all goes well, the holly seeds should germinate by spring. Otherwise, they'll have to remain through another winter.

Steps for Ilex glabra (Inkberry Holly) Propagation with Wood Cuttings

Now, there are two types of Holly cuttings that you can use for propagation. The most popular cuttings are those taken from hardwood growth during cold weather or their dormant period.  However, you can also use softwood cuttings taken in summer or late autumn.
For hardwood cuttings, you should cut above and below the bud unions from the branches for best growth. If you want to use softwoods, cut about 0.24 inches (0.6 cm) below a leaf node.
Once this process is complete, dip the cut ends into rooting hormone then plant your cuttings in a mixture of potting soil and sand. Holly cuttings need a well-lit location and regular watering to develop a healthy root system. Once established, you can transplant each baby plant in its permanent spot.
Ilex glabra

How to Care for Ilex glabra (Inkberry Holly)

Light

This shrub prefers full sun, especially in cooler climates. It can, however, tolerate partial sun and may appreciate some shade in warmer areas.

Soil

Inkberry is best planted in average, medium to wet soils and in full sun to part shade. It is adaptable to both light and heavy soils but does best in rich, consistently moist, acidic soils. It does not do well in alkaline soils. In native locations, it prefers sandy, acidic woodland soils and is often found along the edges of swamps and bogs.

Water

All shrubs should be watered 1-2 times per week, depending on the weather. Trees do not require more watering, except in drought conditions where there is less than 1 inch of rain per week. Groundcover, however, should be watered 3 times per week for 3 months.

Temperature and Humidity

Inkberry holly thrives in a wet, cool climate. This distinguishes it from other hollies, which often prefer drier locations.

Fertilizer

fertilize all your shrubs, evergreens, trees, groundcover, and perennials once every 3 weeks. This should be done during the months of April, May, June, July, and August.

Pruning

Holly Inkberry is a shrub that should be pruned in the late spring to maintain the shape and height of the plant.
In general gardening terms, pruning is probably the most misunderstood gardening chore, and certainly, the chore that is most likely neglected. When we specifically look at pruning with regards to Hollies, this misunderstanding and negligence can be magnified.
Pruning has been described as a “combination of art and science.” I personally find pruning to be one of the most relaxing yet rewarding chores in the garden. Pruning a specific plant to look a specific way, involves art in creating a unique definition for a specific plant, and it involves science in understanding the physical growing habits of the plant to be pruned.
Ilex glabra

Pests and Diseases

  • Leaf Spot
The leaf spot disease that affects inkberry is called anthracnose. Anthracnose appears as light tan to darker brown circular or irregular spots on the leaves. It spreads through spores in moist weather, which you can see with your naked eye as pinprick-sized pink dots in the leaf spots. To control, prune out diseased limbs and/or apply a fungicide containing thiophanate-methy or chlorothalonil until the disease is gone. To prevent anthracnose, avoid overhead watering.
  • Root Rots
Root rots can also affect the inkberry holly, especially Phytophthora and Thielaviopsis black root rot. They both cause yellowing of the leaves, early leaf drop, slow growth and, eventually, branch dieback, and occur most often with flooding and extreme heat. Fungicides cannot cure the holly plant of this disease but can stop the spread. Thiophanate-methyl will help with Thielaviopsis root rot and etridiazole and metalaxyl with Phytophthora. As the diseases cannot be cured, prevention by planting the inkberry in well-draining soil is your best bet.
  • Cankers
Botryosphaeria canker affects weaker inkberry plants, usually following extremely high or low temperatures and drought. The canker causes similar symptoms to root rot, including yellowing of the leaves and dieback. The cankers appear as sunken or cracked patches of wood, and girdle the stems so nutrients cannot reach the leaves. Prune out diseased branches as you notice them and take better care of the holly, watering during drought and mulching to retain soil moisture.
  • Pests
Most pests don't bother inkberry, but some do. Aphids attack new growth and scale insects are sometimes a problem, but both can either be removed by hand or with a quick blast of water. The inkberry leaf miner can be a larger problem, creating ragged leaves. In small infestations, you can pick the leaves off the plant, while larger infestations may require pesticides. During droughts, spider mites can also appear.
Ilex glabra

Varieties of Ilex glabra (Inkberry Holly)

Densa grows to 3 to 4 feet in height with a slightly greater width.
Compacta grows to 3 to 4 feet in height with a spread up to 6 feet. It has a tighter, more rounded growth habit than other forms.
Shamrock grows to 4 feet in height and spread. It has bright green foliage and is known to sucker less than other varieties.
Ilex glabra

Ilex glabra (Inkberry Holly) FAQ

How tall does inkberry get?

In the wild, inkberry holly is often found in bogs, but it grows just fine in typical garden soil. It's a broad spreading, semi-stoloniferous shrub 6 to 8 feet tall and 8 to 10 feet wide.

Is Ilex glabra toxic?

Warning: All Ilex species may be somewhat toxic if ingested. Sensitivity to a toxin varies with a person's age, weight, physical condition, and individual susceptibility. Children are most vulnerable because of their curiosity and small size.

Is inkberry holly edible?

While the berries aren't edible for humans, many birds and small animals are fond of them in the winter. Growing inkberry holly in your yard is a simple project, as these plants are almost carefree.