The low-maintenance broadleaf evergreen Dahoon holly tree is distinguished by its glossy dark green leaves devoid of the sharp edges typical of many hollies, as well as its characteristic bright red berries. The plant can become a miniature tree trained to have a single leader acting as a trunk, or it can grow into a big multistemmed shrub. Dahoon holly grows best in areas that are naturally moist with lots of sun, and in temperatures that range from mildly cool to warm. Like many other holly species, dahoon holly has berries that are somewhat harmful to both people and animals due to saponins.
Dahoon Holly Tree Overview
| Common Name | Dahoon holly, cassine holly |
| Botanical Name | Ilex cassine |
| Family | Aquifoliales |
| Plant Type | Tree, shrub |
| Mature Size | 20–30 ft. tall, 10–15 ft. wide |
| Sun Exposure | Full, partial |
| Soil Type | Moist but well-drained |
| Soil pH | Acidic, neutral |
| Bloom Time | Spring, summer |
| Flower Color | White (female), green, white (male) |
| Hardiness Zones | 7–11 (USDA) |
| Native Area | North America |
| Toxicity | Toxic to humans, cats, dogs, and horses |
Dahoon Holly Care
These are the primary maintenance needs for dahoon holly plants.
- When the temperature is cooler, plant the tree in late fall or early spring.
- These trees will stretch out 12 to 15 feet, so give it lots of room to flourish. For a screening hedge, plants can be placed a little closer together.
- Dig a hole twice or three times wider than the depth of the container before planting. Backfill with soil after placing it in the hole a little higher than it was in its container.
- These trees require regular watering; they are not drought-tolerant.
Light Requirements
Although dahoon holly prefers full sun, it may tolerate partial shade as long as it gets two to six hours of direct sunlight per day.
Soil
As befits a plant that naturally occurs in the bogs, swamps, and moist forests of the Gulf Coast from Florida to Texas, dahoon holly prefers constantly moist soil. It can grow in sandy, clay, or loam soils; however, if the soil is already dry, the roots will need to be watered frequently.
Watering
The optimal growing conditions for dahoon holly are those that closely resemble the marshy, consistently wet environments found in its natural habitat. To keep the soil moist after planting, add two inches of mulch on top. Throughout the first year, give the roots plenty of water. When there is a drought, make sure to water more frequently. The roots will seek out any source of moisture and become stressed if they are not properly watered.
Temperature and Environment
Dahoon holly thrives in zones 8 and 9, while it can withstand zones 7a to 11a. Zone 7 might require some winter gear. Zones 10 and 11’s high humidity levels are well tolerated by it, albeit growth will be a little more muted there. It can tolerate salt rather well.
Fertilization
Dahoon holly doesn’t require frequent feeding, but if your soil is alkaline, giving it an annual dosage of acidifying fertilizer per the directions on the container could help avoid chlorosis (yellowing of the leaves).
Types of Dahoon Holly
‘Angustifolia’: The leaves on this dahoon holly cultivar are thin. It could be difficult to locate this species in the nursery trade outside of its natural growing region.
Ilex x attenuata hybrids: The genetic progenitor of numerous other well-known hybrid hollies, such as the Ilex x attenuata cultivars “East Palatka,” “Hume #2,” and “Savannah,” is the dahoon holly. It might be simpler to locate these cultivars than the species type.
Pruning
Pruning on a regular basis is not necessary for an established dahoon holly. It does, however, voluntarily tolerate severe pruning to shape it, just like most hollies. Pruning promotes a robust, well-formed tree. This holly tree is also good and is frequently used for practicing bonsai.
Pruning berry-producing evergreen hollies, such as dahoon, is best done during the late winter dormant phase so as not to remove visually pleasing berries that develop throughout the summer growing season. Pruning them in the summer soon after flowering is another option, but doing so will destroy the berries of the current season; if you do this, be ready for a winter without the vibrant red berries.
Although the method of pruning depends depend on the desired outcome, it’s often a good idea to start by cutting off any branches that rub or cross one another. When the plant is young, competing leaders can be trimmed away to favor a central leader that will act as a trunk, giving the appearance of a more typical tree.
Trim back the tips of the branches at the end of the pruning session, if the plant is to be used as a hedge, to create the necessary outline. If at all feasible, avoid pruning the canopy since it has an open habit and twisted, small-diameter branches that drop to provide an efficient privacy screen from the main stems.
Propagating Dahoon Holly
Evergreen hollies are more frequently propagated by taking stem cuttings and rooting them because seed propagation is a laborious and time-consuming procedure. This can also take some time, but it’s not hard to complete; here’s how:
- Use sharp pruners in the middle of summer to trim 3 to 5 inch segments off the tops of newly growing branches. Remove all leaves except the upper three or four.
- Plant the cuttings in pots with a sand and perlite combination after dipping the cut ends in rooting hormone. After moistening the potting material, put the pots inside plastic bags that are loosely packed.
- Place the pots in bright indirect light in a relatively warm area (60 to 70 degrees Fahrenheit). Check the cuttings every week, and if the growing medium gets dry, give them a little water.
- After four to six weeks, when a good root system has formed, take the plastic bags off and place the pots somewhere bright, like a sunny window. In warm-winter regions, the potted cuttings can be grown outdoors.
- Transfer the cuttings that are actively growing after a few months into bigger pots that are filled with regular potting mix.
- After winter, keep the plants growing in a sunny spot, and when springtime arrives, transplant them outside.
How to Grow Dahoon Holly From Seed?
Growing hollies from seed can be challenging because the seeds need two to three years to germinate. Additionally, each plant only produces one type of flower—a male or female flower—because the plants are dioecious. This indicates that the fruit of a female dahoon holly plant is likely to yield sterile seeds unless you are cultivating both male and female plants close to one another.
Follow these procedures if you decide to experiment with seed propagation:
- When berries are ripe in the fall, remove the skins and break them open to reveal the seeds within.
- After giving the seeds a quick rinse with cold water, put them in a big, flat tray with regular potting mix in it.
- For the winter, cover the trays and set them outside in a covered area. It can take up to two or three years of repeated winter frost before the seeds develop, so you’ll need to exercise extreme patience.
- When the seeds do eventually sprout, move the seedlings into separate pots with caution so they can continue to thrive.
- Once they have grown in pots for an additional year, they have to be prepared for outdoor planting.
Potting and Repotting Dahoon Holly
Dahoon holly is by nature a slim, reasonably well-behaved plant that takes pruning well, even though container cultivation is not frequent. When planted in a large, heavy container that drains well and is filled with a good moisture-retentive potting mix, it makes an excellent container tree for the patio or deck. But since these plants don’t like to be repotted, it’s preferable to select a large container from the beginning.
Dahoon holly is also practiced in bonsai. The plants are frequently trimmed of their roots, while new branches are continuously chopped off and guided by wires. To trim the roots, the plant is gently taken out of its pot.
Overwintering
In general, dahoon holly doesn’t need to be protected from the winter cold. If you live in zone 7, though, you might find that covering the shrub with burlap during the coldest months keeps the leaves from drying up and getting winter burn.
Because the bark on these trees is rather thin, young specimens might benefit from having hardware cloth placed over the trunk to keep animals like rabbits and other animals from eating the bark. Additionally, by shielding the trunks, you can stop mowers and other mechanical devices from damaging them. For elder trees, this protection is not necessary.
To maintain soil moisture, make sure to mulch the land heavily in places with dry winters.
Common Pests and Plant Diseases
Apart from occasional trimming, dahoon holly requires very little upkeep and is rarely affected by pests or plant illnesses.
Although the tree is highly vulnerable to two-lined spittlebugs, which produce foamy trails of excrement as they feast on leaves, insect pests also normally avoid dahoon holly. Thoroughly infected trees could lose their foliage. Treating squirrelbugs is rather simple: just blast the leaves with water to get the bugs out of the way. A thorough cleaning beneath the tree will get rid of the eggs and stop another infestation.
While scale insects, mites, and leaf miners occasionally munch on leaves and stems, the damage they cause is rarely severe enough to need treatment. These pests are more likely to proliferate in dry environments.
This tree does not appear to be susceptible to fungus diseases that afflict many other hollies. If the plant is infected with a fungus, you may notice swelling (twig gall) on the leaves or twigs; however, these growths normally go away on their own and don’t need to be treated.
How to Get Dahoon Holly to Bloom
Bloom Months
On this tree, late spring brings the blossoms, which are not particularly spectacular. In the spring, female plants bloom, and then in the winter, they bear red berries that draw in wildlife.
What Do Dahoon Holly Flowers Look and Smell Like?
Female trees have white blossoms. The male tree has greenish-white colored blooms. The mildly sweet aroma of both varieties of flowers is intended to draw pollinators.
How to Encourage More Blooms
Unless you want the red berries that come after a female tree blooms, there’s really no reason to be concerned about a holly tree that doesn’t flower. If the tree doesn’t bloom, you might need to exercise patience because young trees don’t usually start to bloom (or bear fruit) until they are three or four years old.
If the tree blooms in the spring but does not bear berries in the fall, it is probably a male tree that will never bear fruit. It is advised that farmers who wish to have an abundance of berries establish at least one male tree to aid in pollinating neighboring female trees.
Deadheading Dahoon Holly Flower
Inadequate pruning timing can momentarily disrupt these plants’ flowering/berrying cycle. You will be snipping off the flower buds and destroying the berry crop for that year if you prune in the early spring just as new growth is starting. Pruning should be done in the winter, when the plants are dormant.
Common Problems With Dahoon Holly
Most of the concerns associated with other holly species do not apply to this plant. Plants that receive regular irrigation are healthier and more resilient to most issues. But keep an eye out for the following problems.
Yellowing Leaves
A holly that thrives in excessively alkaline soil, like many other acid-loving plants, may experience chlorosis, a disease that causes the leaves to turn yellow while the veins remain a dark green color. Here, the best course of action is to reduce the pH of the soil by applying an iron-boosting amendment or treating the plant with an acidifying fertilizer (such as an azalea-specific one).
Shriveled Brown Leaf Tips
Occasionally, late winter’s sharp temperature swings can cause burn on dahoon holly leaves. The tree readily heals, thus there is no long-term damage caused by this.