How to Grow and Care for Inkberry Holly
Strongbox is a female variety and will develop black berries if a compatible male pollinator is planted in the vicinity.
Strongbox ® Inkberry holly Ilex glabra
The optimum amount of sun or shade each plant needs to thrive: Full Sun (6+ hours), Part Sun (4-6 hours), Full Shade (up to 4 hours).
Plant Strongbox inkberry holly anywhere you’d use boxwood – as a hedge, edging, or specimen. Strongbox inkberry holly is a bit broader and less rounded than our other inkberry holly, Gem Box ® .
Little care is needed to enjoy Strongbox inkberry holly in your landscape. It has shallow roots, so a 2-3″ layer of mulch is a good idea. If you wish to trim or prune it, do so in mid-late spring, after the new growth has emerged.
Strongbox is a female variety and will develop black berries if a compatible male pollinator is planted in the vicinity.
The berries of inkberry holly were used by Civil War soldiers to make ink for their personal correspondance. To get berries on Strongbox inkberry holly, plant a male Squeeze Box holly within 50’/15m.
Strongbox ® Ilex glabra ‘ILEXFARROWTRACEY’ USPP 30,147 , Can 6,516
11 Reviews
Browse reviews from people who have grown this plant.
I bought 6 of these last year to make a casual hedge along an open aluminum fence. Now all of them are bare halfway down the plant. They are planted per tag instruction and were very full when I bought them (though I hesitated due to other reviews listed here) and I have to say I’m very disappointed. From the research done online regarding inkberry hollies, some say to prune them along the top so that they fill in across the bottom. However if I prune them across the top I will lose the only part that actually has leaves. Now I’m trying to decide if I should leave them for another year in hopes they will bounce back, or toss them (and my money) out to the curb.
I bought 6 of these last year to make a casual hedge along an open aluminum fence. Now all of them are bare halfway down the plant. They are planted per tag instruction and were very full when I bought them (though I hesitated due to other reviews listed here) and I have to say I’m very disappointed. From the research done online regarding inkberry hollies, some say to prune them along the top so that they fill in across the bottom. However if I prune them across the top I will lose the only part that actually has leaves. Now I’m trying to decide if I should leave them for another year in hopes they will bounce back, or toss them (and my money) out to the curb.
I bought 10 of these shrubs, one died the first year and the rest are growing well. No complaints but I have noticed the inkberry is a slow grower so if you want an instant garden I suggest buying the 3 gallon.
I was able to pick up several of these inkberry plants from my local nursery to use as a hedge up against my porch – They like sun and I have found them to be easy to care for – drought tolerant. Last year I saw some Whitefly on the woody stems and was able to eradicate them by spraying with ‘Sevin’ – I shape and cut them back quite a bit each Spring as they fill in very quickly and provide a really good looking hedge – I love the year around Greenery – All in all I am very happy with my purchase and I am looking to do another border hedge in my yard with these shrubs planted up against ‘open’ aluminum fence panels.
How to Grow and Care for Inkberry Holly
David Beaulieu is a landscaping expert and plant photographer, with 20 years of experience.
Inkberry holly is a slow-growing broadleaf evergreen shrub with a rounded-to-upright growth habit. It is easy to grow and offers good winter color.
The name “inkberry” is a clear reference to the dark fruits produced by the shrub, as is the plant’s secondary common name, “gallberry.” This alternate name derives from the fact that black ink was once made from the galls of oaks.
In the taxonomical name, Ilex glabra, the species epithet, glabra, means “smooth,” referring to the plant’s smooth leaves, which are quite different than the prickly leaves of more common hollies. However, be aware that the leaves and berries have toxic qualities to both humans and pets.
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
Inkberry needs quite a bit of water after it is established and more so as it is becoming established. You will need to water at least once a week, especially if the weather is dry.
Temperature and Humidity
Inkberry holly thrives in a wet, cool climate. This distinguishes it from other hollies, which often prefer drier locations.
Fertilizer
Fertilize in spring with a fertilizer such as Holly-Tone. If your soil is alkaline, consider amending it before planting your inkberry.
Types of Inkberry Holly
There are a few varieties of inkberry including:
- ‘Densa’ grows to 4 to 6 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 to 5 feet in height and width. It has bright green foliage and is known to sucker less than other varieties.
- ‘Nigra’ grows 6 to 10 feet in height and width. It has dark green foliage.
- ‘Nordic’ grows to 3 to 4 feet in height and width. It has dark green foliage, with a distinct broad pyramidal growth habit, and has larger leaves than other varieties.
Pruning
Pruning should be done in late winter or just after blooming. Inkberry blooms on old wood, so pruning needs are minimal unless you are using the shrubs in a hedge. Some species tend to get leggy and should be pruned in late winter to reshape and allow the plant to fill out. Because the blooms on inkberry are produced on old wood, not the new growth, you might sacrifice flowers and fruit if you wait too long to prune. It’s best to wait till after the blooms are spent to prune the plant. Remove root suckers regularly if you don’t want the shrubs to colonize and spread.
Propagating Inkberry Holly
Inkberry self-propagates by spreading root suckers. In fact, it can take over an area rapidly if it’s not checked. You can slow the pace of growth by removing the suckers each year, which can be planted in other areas of your yard if you’d like.
If you want to propagate them on your own, you can do so with cuttings. Here’s how:
- Using pruning shears, cut off a 6-inch piece of new growth from a healthy branch.
- Dip the cut end into a rooting compound powder or gel.
- Select the appropriate spot for your new plant and push the cut end into the soil, approximately 1-inch deep, and water. Keep the soil moist but not over wet.
You can also put cuttings in water to root, which will take about four weeks. And then plant in the desired location.
Overwintering
Inkberry holds up well during the winter months. Interestingly enough, some species will have their leaves turn a deep purplish color in the winter.
Common Pests and Diseases
Inkberry is a very easy-to-grow plant with few serious insect or disease problems and is deer-resistant. Leaf spot is an occasional problem. Spider mites sometimes appear, especially in dry conditions. Powdery mildew, a fungi, can appear mainly in warm and humid environments. These issues can be taken care of with a fungicide or neem oil treatment. The shrubs are also susceptible to chlorosis (yellowing of the leaves) if they are planted in high pH alkaline soil.
Inkberry holly should be planted just to the top of the root ball. If you plant up to where the branches meet the roots, that’s too deep.
With the right conditions and proper care, inkberry holly can live for 40 years or more. There are some holly plants that have lived as long as 100 years.
What are common companion plants to put with inkberry holly?
Plant some viburnum, hydrangea, or rhododendrons along with inkberry. Some edging plants that look well in front of inkberry holly include impatiens, geraniums, begonias, and coleus.
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- Holly Berries. Poison Control, National Capital Poison Center.