Sky Pencil holly (Ilex crenata ‘Sky Pencil’) is a versatile plant with dozens of uses in the landscape. It is unique and has its own style. The thin columnar shape is the first thing you’ll notice. It grows no wider than 2 feet (61 cm.) when left to grow naturally, and it can be pruned to just a foot (31 cm.) in width. It’s a cultivar (cultivated variant) of Japanese holly with evergreen leaves that looks more like boxwoods than hollies. Continue reading to learn how to grow a Sky Pencil holly and how simple it is to care for this fascinating plant.
Sky Pencil hollies are narrow, columnar shrubs that can reach 8 feet (2 meters) in height and 2 feet (61 cm) in width. With pruning, you may keep them at a height of 6 feet (2 meters) and a width of 12 inches. (31 cm.). Female plants yield tiny, black berries and produce little, greenish blooms, although neither is very beautiful. They are mostly grown for their unique shape.
Sky Pencil holly shrubs thrive in containers. As a result, you can use them as architectural plants to frame a door or entryway, as well as on decks and patios. Because the leaves aren’t spiky like other varieties of holly shrubs, you don’t have to worry about coming into touch with the plant.
Sky Pencil holly shrubs can be used as a hedge plant in the ground. They are useful in areas where the width of bushier plants is restricted. They seem well-kept even with little trimming, and they can be used in formal gardens alongside beautifully sheared plants.
The USDA plant hardiness zones for Sky Pencil hollies are 6 through 9. They can grow in full sun or slight shade. In zones 8 and 9, give shade from the hot midday sun. Strong winds must be avoided in zone 6. It thrives in any well-drained soil.
Dig the planting hole twice as deep as the root ball and twice as wide. If your soil is heavy clay or sand, combine some compost with the fill material. As you backfill the hole, press down with your foot to remove any air pockets.
After planting, water thoroughly and add more fill dirt if the soil settles. Water frequently until the plant is established and growing, then apply 2 to 4 inches (5-10 cm.) of organic mulch over the root zone to help keep the soil moist. You won’t need to fertilize your new holly until the first spring after planting.
Sky Pencil hollies require very little maintenance once established. They don’t require cutting unless you wish to keep them at a certain height or width. If you want to prune them, wait until the plants are dormant in the winter.
In the spring, use one pound of 10-6-4 or a specific broadleaf evergreen fertilizer per inch (2.5 cm.) of trunk diameter to Sky Pencil hollies. Water in the fertilizer after it has been applied to the root zone. Watering established plants is only necessary during dry spells.
Sky Pencil Holly Ilex crenata grows well in USDA zones 6 through 9. In the ground, these shrubs adapt well to varying sunlight conditions. It will need protection from the midday sun in hardiness zones 8 and 9.
While in zone 6, it needs protection from winds.
Another key consideration is to dig a hole three times the width of the root ball when planting your shrub in the ground. Backfill the hole with compost mixed in with the soil. Even so, it’s a good idea to learn the fundamentals of Holly care before excavating a hole.
Sky Pencil Holly may grow in a variety of soil conditions, including sandy, clay, and rock. However, it is critical to give the shrub with loose, loamy soil. So it requires well-drained soil and, if the soil is clay or sand, it is beneficial to add some compost to the mix.
Another thing to note is that the Japanese Holly is an all-female cultivar, and if you want it to bear fruit, you must also have a male variety.
These columnar shrubs prefer full sun, but partial shelter from the hot afternoon heat is beneficial in warmer climes. If you live in a cooler region, however, full sun is recommended. Your adaptive plant need at least six hours of morning sun daily.
When Ilex crenata is not given enough sunlight, it grows slowly and its branches become less dense.
Watering fresh Holly plants frequently will help the roots establish. However, the soil must be moist and not soggy, as this raises the risk of fungal infections and root rot. During dry conditions, water more frequently until the root ball establishes itself.
Another thing to remember, like with most indoor plants, is to let the soil dry between waterings. Then, in warmer climates, water regularly when the soil appears to be dry. Finally, if you’re worried about overwatering, pay attention to the leaves.
The leaves should be dark green. Overwatering is indicated by the lightening of the foliage. A lack of watering causes your plant to turn brown.
The Sky Pencil Hollies like temperate conditions because they do not thrive in harsh heat or cold. As a result, it is advisable to select a location that protects them from the wind. Furthermore, the plant is sensitive to extreme humidity.
When the young plant grows older, it will require less water because it is resistant to drought. To avoid winter burns and to protect against freezing temperatures. To keep the branches tight, bind them together or wrap them from top to bottom.
Alternatively, cultivate your columnar shrubs in containers and transplant them to a warm location.
When planted in fertile organic soil, your Ilex crenata Sky Pencil usually does not require feeding. All you have to do is mulch around the base. However, if your plant need assistance, you can use an all-purpose slow-release balanced feed once a year in the spring.
Water your shrub thoroughly after applying the feed. However, you do not need to fertilize your young Holly during the first year because it does not develop quickly. Expect a four to six-inch vertical growth from an established Ilex crenata.
Another key point to remember is to avoid using heavy nitrogen fertilizers to force your plant to grow. Providing forced growth makes your Japanese Holly susceptible to diseases over time.
You can grow your tiny Japanese Holly types in containers. We recommend using a pot that is at least eight inches broader than the root ball. This permits your Sky Pencil to grow for three years before it requires a larger container.
We recommend selecting terracotta because the moisture evaporates faster and will not collapse over with the growth of your plant. Also, be certain that it has enough drainage. Finally, to keep its shape, the Sky Pencil Holly will require light trimming.
The optimal period to prune is from spring to early fall, however major pruning can be done in early spring before new growth. You can also promote development by remove diseased, dead, or damaged branches.
It will take a few prunes over the growth season to shape your Sky Pencil Hollies into a hedge in the landscape. If you have an old shrub that needs to be refreshed, cut it down to 12 inches off the ground in late winter.
Pests and other issues, such as high winds damaging the leaf, can make the Japanese Holly their home. In addition, in late April, a female Holly Leaf Miner can suck out the fluids of the leaves.
Whiteflies, spider mites, and scale are among the other insects. Stem cankers, root rot, and nematodes are common plant diseases. Another issue to be concerned about is yellowing leaves caused by too-alkaline soil, which can lead to iron shortage but is uncommon.
To address the issue, use a fertilizer meant for acid-loving plants and shrubs.
Because Japanese holly is dioecious, you’ll need two plants, one male and one female, if you want berries. It is important to note that the shrub will not produce berries until it is six to eight years old.
It has a similar appearance to boxwoods, which is why it is also known as box-leaved holly, but it is a separate species.
It grows six to twelve inches per year, depending on the cultivar, and is classified slow to medium.
Yes, Japanese Holly is toxic and should be kept away from children and pets.
The yellow leaves are caused by an iron deficit caused by too little alkaline in the soil and can be remedied with an acid-loving shrub and tree fertilizer.
As long as you start it healthy, Japanese holly is a relatively low-maintenance plant.
When taken care of properly for, a Japanese holly may live for 50 years or more.