Blue holly is a member of the Ilex genus and the Aquifolicaeae family. These shrubs are typically known for their glossy leaves, often but not always evergreen, and their brightly colored berries.
Evergreen shrubs play a crucial part in a landscape. Planting blue hollies in a foundation garden will provide year-round coverage and beauty. Hollies can be especially useful as a hedge or a privacy screen.
These large, beautiful hollies are surprisingly easy to care for and deserve a place in your landscape. Let’s dig in if you want to add blue hollies to your garden!
Overview
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What Is It?
Blue holly, a hybrid of Ilex rugosa and Ilex aquifolium, enhances landscapes.
If you love holly bushes, you will love blue holly. It is a cross between Ilex rugosa and Ilex aquifolium. This combination of plants produces a new and improved holly suitable for many uses in your landscape.
Characteristics
This cold-tolerant hybrid features glossy, spiny, blue-green leaves.
Blue holly is an evergreen shrub hybrid. This particular plant was hybridized for improved cold tolerance and beautiful blue-green leaves.
The blue-green leaves are glossy and moderately spiny. This holly is dioecious, meaning there are male and female forms. Plant at least one male holly for every three to five female hollies if you desire bright red berries.
Native Area
This holly hybrid combines European and Asian species.
Blue holly is a hybrid holly created by breeding two different species of hollies together. Therefore, it is not truly native anywhere other than the garden of its creator, Kathleen Meserve of St. James, New York, where it was developed.
The first holly used, Ilex aquifolium, is native to Europe. The second holly, Ilex rugosa, is an English-style holly native to regions of Asia. Neither one is native to North America, although both grow well here.
Planting
The best time of year to plant this shrub in warm regions is early fall. Plant in the spring if you live in cooler areas. These planting times will allow your blue hollies’ roots to grow and strengthen before hot weather arrives.
Transplanting
Dig a hole double the size of the rootball, place it evenly, backfill, and water regularly.
Once you have your ideal spot located in your garden, it is time to transplant.
- Begin by digging a hole twice as wide and twice as deep as the rootball. Keep this step in mind when you are purchasing your holly. These plants can be quite large.
- Place the holly into the hole, ensuring the plant crown is even with the soil line. Spin it around so it is situated just the way you want it.
- Backfill the hole with your garden soil.
- Water deeply and keep the soil moist throughout the first growing season, supplementally watering during dry periods.
Growing from Seed
Growing blue holly from seed is lengthy and best suited for professionals due to slow germination.
While it is possible to grow these hollies from seed, it is not the best method. It can take over one year for the seed to germinate in perfect conditions. This is a task best left to the professionals. Instead, buy a healthy plant from your local nursery.
How to Grow
Blue hollies offer tremendous beauty to your garden with minimal effort. These plants do not require special gardening skills, just a bit of planning and executing! Let’s dig in!
Light
Blue holly thrives in 6 hours of sunlight.
Blue holly grows best in full to partial sun, right around six hours of sunlight. If you live in a warmer zone, provide the shrub with some afternoon shade.
Water
Maintain balance by providing one inch of water per week and avoid waterlogging.
To keep a blue holly happy, you must find the perfect balance of rainfall and irrigation. These shrubs need to be watered, and the soil should be kept moist, but keep the soil from becoming waterlogged. About one inch of water per week will be perfect.
You will need to water a bit more regularly for newly planted blue hollies. Do your best to keep the soil moist, and don’t let it dry out for the first growing season.
Soil
Blue hollies tolerate diverse soils but thrive in well-draining, acidic soil.
Blue hollies are tolerant of various soil types but must grow in well-draining soil. Hollies generally prefer acidic soil, which is any soil with a pH of 6 or less.
Temperature and Humidity
Blue hollies thrive in zones 4-9, so verify your zone before planting to avoid winter damage.
Blue hollies are hardy in zones 4-9. Check to make sure you live within these zones before planting this shrub. Too much exposure to cold temperatures and chilly winter winds can damage or weaken the plant.
Fertilizing
Use holly-specific fertilizer to enhance berry production, ideally in spring and late fall.
To promote beautiful and prolific berries, use a fertilizer suitable for hollies, such as Espoma Holly-Tone. This fertilizer will support acid-loving plants by helping them take up all available nutrients in the soil.
Follow the application instructions on the package. The best times to apply fertilizer to hollies are in the spring and again in the late fall.
Maintenance
Pruning is optional for shaping or removing damaged branches.
Blue hollies are beautifully low-maintenance shrubs. Aside from the above-mentioned, pruning is the only other maintenance you may need to complete.
Pruning your blue hollies is not required and should only be done to perfect the shrub’s shape or remove damaged branches. The best time to prune is late winter or early spring. This will prevent any accidental snipping of flower buds.
Propagation
Are you looking to propagate your blue holly and grow your collection? The best propagation method for these shrubs is cuttings, which is best done from late spring to early summer.
Cuttings
Take a 6-8 inch stem cutting, dip in rooting hormone, plant in sandy mix, keep moist until rooted, then transplant.
If you want to take stem cuttings, here is how to do it:
- Take a cutting that is anywhere from 6-8 inches long. Be sure to use clean, sharp shears.
- While it is not required, this is the time to dip the end of your cutting into rooting hormone powder to help speed root formation.
- Stick your cutting down into a container filled with sandy potting mix.
- Place your cutting in a bright area that does not receive direct sunlight.
- Keep the soil consistently moist until roots have formed.
- After a few weeks have passed, you should feel resistance from your cutting if you give it a gentle tug. This is a sign that roots have developed.
- Transplant your cutting or plant into your garden!
Popular Varieties
While there are many varieties, here are a few more popular and available ones for your garden!
Blue Girl
A compact holly with evergreen blue-green leaves and vibrant red winter berries, ‘Blue Girl’ is ideal for hedges.
 | botanical name Ilex x meserveae ‘Blue Girl’ |
|---|---|
 | sun requirements Full sun to partial shade |
 | height 6-8 feet |
 | hardiness zones 5-9 |
‘Blue Girl’ is a smaller variety but still packs a beautiful punch. The blue-green leaves remain throughout the year, while the berries are bright red in winter.
Plant ‘Blue Girl’ as part of a hedge or foundation garden. Pair the female plant with a male such as ‘Blue Boy.’
Blue Maid
This classic holly cultivar has deep blue-green leaves, purple stems, and abundant winter berries.
| | botanical name Ilex x meserveae ‘Blue Maid’ |
|---|---|
| | sun requirements Full sun to partial shade |
| | height 8-10 feet |
| | hardiness zones 5-9 |
‘Blue Maid’ is a classic-looking holly. Deep purple stems accent the deep blue-green leaves. The red berries are prolific in the winter.
Plant this conical holly as part of a mixed border, on a woodland edge, or as a statement piece to your foundation garden. Pair ‘Blue Maid’ with a male variety such as ‘Blue Stallion.’
Blue Princess
A popular, large blue holly, ‘Blue Princess,’ has white spring flowers and red berries.
| | botanical name Ilex x meserveae ‘Blue Princess’ |
|---|---|
| | sun requirements Full sun to partial shade |
| | height 10-15 feet |
| | hardiness zones 4-9 |
‘Blue Princess’ is a very popular variety. This large holly has an upright and busy growth habit. In the spring, the holly will produce white flowers to make way for beautiful red berries.
Because ‘Blue Princess’ is a female holly, it will need a male companion to produce berries. ‘Blue Stallion’ is an excellent choice. Plant this shrub in a mixed evergreen border, as a hedge, or as a part of your foundation planting.
Castle Spire
This attractive, pyramidal holly has small, toothed leaves and vibrant winter berries.
| | botanical name Ilex x meserveae ‘Castle Spire’ |
|---|---|
| | sun requirements Full sun to partial shade |
| | height 6-10 feet |
| | hardiness zones 5-7 |
‘Castle Spire’ is a beautiful, upright-growing holly that grows into a very attractive pyramidal shape. It features small, oval, toothed leaves.
In the wintertime, the red berries will liven up your landscape. Plant with a male blue holly such as ‘Castle Wall.’
Common Problems
Hollies are generally problem-free. With any plant, however, it is always possible that the growing environment can introduce some pests. Let’s consider the more common pests, how to treat them if required, and how to prevent them.
Pests
Here are a few common insects you may find living on your plant. These pests can be easily prevented with good plant care and can be eradicated with a few basic steps.
Aphids
Aphids can often be knocked out with a solid water spray, but other control methods are available if needed.
These little green nightmares are known to wreak havoc on our plants. However, they are not quite as deadly on a large evergreen shrub.
Aphids suck on the plant juices from leaves and stems. If you notice these insects, first try removing them with your hose spray. Grab some neem oil or insecticidal soap from a garden center if that doesn’t work.
Leaf Miners
Combat holly leaf miners by removing and disposing of affected leaves and avoiding compost.
Hollies have a specialized leaf miner, the holly leaf miner. The larvae of these insects hatch in between layers of leaves and nibble away on everything in sight. The eating patterns leave squiggly lines on the surface of the leaves.
Remove any infected leaves and destroy them. Do not add them to your compost. If the problem persists, you may need to call in the help of some plant care specialists.
Scale
Tackle Holly scale with horticultural oils to eliminate and prevent black sooty mold.
Holly scale looks like green bumps on the backside of your holly leaves. These little insects create a protective shell around themselves, making them difficult to eliminate.
You may not notice the insects themselves, but you may notice the black sooty mold that forms on their sugary droppings. Horticultural oils can help get rid of these pesky insects. In addition, a cotton swab dipped in isopropyl alcohol can cause scale insects to release from the plant, so if you only have a few, that’s a great way to remove them!
Diseases
Hollies do not have much difficulty with any specialized or difficult diseases. However, some growing conditions can lead to unsightly problems.
Leaf Spot
Combat holly leaf blight with springtime application of an all-purpose fungicide.
Yellow spots on holly leaves are likely caused by one of the many forms of leaf spot. These are fungal diseases caused by one of many different fungal pathogens. This disease will become apparent in the winter when the weather is cool and wet but can be treated with an all-purpose fungicide in the springtime.
Thankfully, leaf spot will not generally cause great harm to your holly. However, some fungal pathogens can spread to other plants, so it’s wise to eliminate the fungal source if you discover this issue in your garden.
Winter Burn
Shield hollies from winter burn by pruning affected leaves in spring and using protection in cool, windy climates.
Often, hollies need winter protection. If you live in a cool climate, or if your blue holly is exposed to wind, you may notice some brown leaves. This is a sure sign of winterburn.
Unfortunately, there is nothing you can do to reverse winter burn, as the damage is already done by the time you identify it. Prune off any affected leaves in the springtime, and remember to cover your shrub with burlap or a frost blanket next winter.
Frequently Asked Questions
The first thing to consider when choosing companion plants is selecting plants that like similar conditions. The blue holly can offer a beautiful evergreen backdrop for hellebore, hosta, bleeding heart, and more.
The berries of the holly plant are toxic to both animals as well as humans. Consider a different shrub, or plant in an area where your family, furry and otherwise, will not be tempted to taste those brightly-colored berries.
If you live in cooler zones, such as 3-5, you may need to provide winter protection for your blue hollies. This could be burlap, extra mulch, a frost blanket, or a plant bag. This is important to prevent the hollies from losing too much water in the leaves or their shallow root systems, which can lead to issues in the upcoming growing season.
Final Thoughts
Blue holly is the perfect choice for gardens in cooler climates. The blue-green leaf-covered stems are beautiful in your gardens and can be used as cut stems for flower arrangements or even stuck into some window boxes.
The red berries illuminate your winter gardens while feeding the birds through the colder months. Don’t forget to plant male and female plants for the maximum effect!
