Inkberry (Ilex glabra)

Appalachian Tea, Gallberry, Inkberry

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.

I. Appearance and Characteristics 

Ilex glabra, also known as Appalachian tea, evergreen winterberry, Canadian winterberry, gallberry, inkberry, dye-leaves and houx galbre, is a species of evergreen holly native to the coastal plain of eastern North America, from coastal Nova Scotia to Florida and west to Louisiana where it is most commonly found in sandy woods and peripheries of swamps and bogs. Ilex glabra is often found in landscapes of the middle and lower East Coast of the United States. It typically matures to 5–8 ft (1.5–2.4 m) tall, and can spread by root suckers to form colonies. It normally is cultivated as an evergreen shrub in USDA zones 6 to 10.

Gallberry nectar is the source of a pleasant honey that is popular in the southern United States.

Spineless, flat, ovate to elliptic, glossy, dark green leaves (to 1.5 inches or 3.8 centimetres long) have smooth margins with several marginal teeth near the apex. Leaves usually remain attractive bright green in winter unless temperatures fall below -17 C/0 F. Greenish white flowers (male in cymes and female in cymes or single) appear in spring, but are relatively inconspicuous. 

If pollinated, female flowers give way to pea-sized, jet black, berry-like drupes (inkberries to 3/8″ diameter) which mature in early fall and persist throughout winter to early spring unless consumed by local bird populations. Cultivars of species plants (e.g. Ilex glabra ‘Shamrock’) typically are more compact, less open, less leggy and less suckering than the species.

II. How to Grow and Care

Sunlight

Inkberry requires an environment with bright and soft light to grow. It grows well in shady places, sheltered on one side, and even in direct sunlight. Mature plants have higher fruit growth rates in places with good light. Young plants, on the other hand, need a shady place (shade cloth can be used) in summer to avoid direct sunlight and prevent sunburn.

Inkberry kept indoors should be placed in sunny rooms, about 50 to 100 cm from the window. Do not place the plant in an environment where light is completely blocked. After extended periods of insufficient light, the plant’s photosynthetic rate will decrease. This will slow down the growth rate possibly to zero, cause thin and weak leaves, and decrease the flowering and fruiting rate.

Temperature and Humidity

Inkberry is distributed in tropical, subtropical, and temperate regions. It thrives in a cool and humid environment. It grows in temperatures ranging from 10 to 31 ℃, is relatively cold-resistant, and can safely overwinter outdoors at about -3 ℃. It grows well at a relative air humidity of 70%, suggesting that arid environments should be avoided.

Watering

Inkberry grows in humid environments and is not resistant to drought. Keep the soil moist during spring and summer. If rainfall is less than 2.5 cm per week when cultivated outdoors, manual watering is required. Water once a day and ensure that the soil around the root system is completely wet. Surplus water should drain away smoothly without accumulating. Spray mist during the day to increase air humidity, which is preferably kept at 70%-90%. After the fruiting period in winter is over, gradually reduce the watering frequency to once a week, and completely drench the soil only if it is completely dry.

It is best to water inkberry in the morning and evening because the temperature around the root system tends to rise if it is done at noon, especially in summer. This will cause damage to the plant. Use rainwater and distilled water rather than tap water, which contains a large amount of calcium and magnesium mineral salts. Long-term use of tap water will cause salinization, hardening, and poor permeability of the soil as well as affect plant growth and ornamental effect. Inadequate or excessive water will both cause the leaves to turn yellow and shed.

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.

Fertilizing

Inkberry does not require much fertilizer. Apply some fertilizer during the growing season to promote luxuriant branches and glossy leaves. Apply thin fertilizer once in early spring and once in early autumn. Compound fertilizer mainly composed of nitrogen fertilizer can make the leaves brighter and bigger.

Stop fertilizing when the temperature is higher than 30 ℃ in summer to prevent root damage. Insufficient fertilization can cause thin and weak plants, sparse fruits, and thin and dull leaves. Large but dull leaves may be caused by over-fertilization and signal that fertilization should be stopped immediately.

Planting Instructions

Though its red fruits are a Christmas symbol, it is generally best to plant inkberry in spring. Large seedlings over 2 years old are preferred for planting. plants should be spaced about 1 m apart and there should be about 1 to 1.2 m between rows. Compacting the soil and watering after planting will allow the roots to be in closer contact with the soil. It should be noted that inkberry is dioecious, so it requires both female and male plants present to produce fruits. Successful pollination only happens when plants are spaced no more than 9 m apart. One male plant can pollinate 6-10 female plants.

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.

Propagation

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.

Transplanting

The prime time to transplant inkberry is during early spring to mid-summer (S3-S5), known as the growing season. This allows it to establish strong roots before winter. Inkberry thrives in well-drained, acidic soil in either full sunlight or partial shade. Remember, water generously and care for it with love!

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.

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.

III. Uses and Benefits 

  • Ornamental uses

Use this evergreen shrub for a hedge, foundation plant, privacy screen, pollinator garden, or rain garden. Inkberry does not grow as densely as other hollies or boxwoods. It tends to become bare at the base as it matures. If desired, select a few stems to prune out in early spring (before new growth begins) to stimulate new growth near the base (a process called thinning).

  • Culinary uses

Honey

Gallberry honey is a highly rated honey that results from bees feeding on inkberry flowers. This honey is locally produced in certain parts of the Southeastern U. S. in areas where beekeepers release bees from late April to early June to coincide with inkberry flowering time.

Beverage

Dried and roasted inkberry leaves were first used by Native Americans to brew a black tea-like drink, hence the sometimes used common name of Appalachian tea for this shrub.

IV. Harvesting and Storage

In suitable growth conditions, inkberry blooms and bears fruits once a year. The fruits appear in fall and winter, and can be appreciated for a long time before picking. Without birds in the yard, the fruits often persist into the next spring. The vase life of fruit-bearing branches after picking is about 20-40 days.

Use sharp garden shears when picking and cut the base of branches at a 45-degree angle, or make the cut into a cross, to increase the water absorption area. Quickly put the cutting in a vase with clean water to avoid water loss. The fruits of Ilex verticillata can also be air-dried since they tend to not drop from the branches. Their colors will change from bright red to deep red, providing good ornamental value.

Inkberry (Ilex glabra) Details

Common name Appalachian Tea, Gallberry, Inkberry
Botanical name Ilex glabra
Plant type Native Plant
Hardiness zone 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b, 9a, 9b, 10a, 10b, 11a, 11b
Growth rate Slow
Harvest time Fall
Height 5 ft. 0 in. - 10 ft. 0 in.
Width 5 ft. 0 in. - 10 ft. 0 in.
Sunlight Full sun (6 or more hours of direct sunlight a day)
Soil condition Clay
Flower color Green
Leaf color Green