When planted right and in the right spot, holly trees are one of the easiest and long-lived trees you'll ever grow.
Holly trees can be grown as large shrubs for use in privacy screen plantings, to frame in the corners of tall homes and other structures, or as a focal point specimen. Lower branches of holly trees can be removed to form very attractive and colorful evergreen trees.
Here's a breakdown of what you need to know regarding how to plant and grow Holly trees like the pros...
Cultural Preferences
Soil Preferences
Most Holly adapt to many soil types. They prefer a moist but well-drained acidic soil of average fertility. Alkaline soils result in chlorosis (yellowing of leaves) which can be corrected by the application of chelated iron and/or soil sulfur. As with so many other types of ornamental plants, constantly soggy or wet soil can cause root rot and other harmful plant diseases.
How To Test Soil Drainage
If you are uncertain about soil drainage in the area you intend to plant your holly tree, it's well worth taking the time to test the drainage before planting.
To test soil drainage, dig a hole 12" wide by 12" deep in the planting area. Fill the hole with water and let it drain. Then, after it drains, fill it with water again, but this time clock how long it takes to drain. In well-drained soil the water level will go down at a rate of about 1 inch an hour. A faster rate, such as in loose, sandy soil, may signal potentially dry site conditions and the need to add top soil or other organic matter to the native soil. A slower rate indicates poor draining soil and is a caution you need to improve drainage or look for plants that are more tolerant of wet or boggy conditions.
Soil pH
Most holly trees grow best in an acid to neutral soil ranging between 5.0 to 7.0 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0. If your soil is alkaline (above 7) the leaves of your plants might turn a paler shade of green, or even yellow. This can be corrected by applying specific nutrients and minerals as suggested below.
How To Test Soil pH
Soil pH is a measurement of the alkalinity or acidity of soil and is measured on a scale of 1-14, with 7 as the neutral mark. Any measurement below 7 indicates acid soil conditions, and anything above 7 indicates alkaline.
If you're unsure about the pH of your soil, and whether or not it's suitable for growing Holly, it's a good idea to test the soil pH in the planting area. You can quickly test soil pH with an inexpensive soil pH tester probe. To raise the pH (make more alkaline) you can add pelletized limestone to the soil. To lower the pH (make more acid) you can apply Soil Sulfur, Aluminum Sulfate, or Chelated Iron. Adding organic compost to the soil or using compost as mulch can also help to increase acidity and maintain acid soil conditions.
Learn More: What is Soil pH and How To Adjust It?
Light Preferences
Most holly tree varieties will grow in full sun or part shade. Foliage will be more dense with more sun. A minimum of 4 hours direct sunlight is recommended for best berry production and foliage density.
Planting A Holly Tree In The Ground
Scroll down for container planting instructions
Step 1
Start by digging your planting hole at least two to three times as wide and only as deep as the height of the rootball of your plant. The wider the hole the better. Place native soil removed from planting hole around the perimeter of the hole, in a wheel barrow, or on a tarp.
Step 2
Depending on the type, fertility and porosity of the soil in the planting area you might need to mix in a soil amendment to the native soil removed from the planting hole. When planting in dense clay or other poor draining soils it is beneficial to thoroughly mix in some good organic matter, such as bagged top soil and/or a good planting mix, at a 25-50% ratio with the soil removed from the planting hole. When planting in very sandy or quick-draining soil adding some top soil, peat moss, compost or other organic matter will help to retain moisture in the soil. When planting in well-drained soils of average fertility there is no need to add a soil amendment.
Step 3
To remove your holly tree from the nursery pot, firmly grasp the plant at its base and gently try to lift and remove it from the nursery pot. If the root ball is stuck in the pot use snips to cut the container away. After having removed the plant from the container, use your fingers or a claw tool to carefully loosen some feeder roots around the surface of the root ball.
Step 4
Set your holly tree in the planting hole so that the top edge of the root ball is at or just slightly above ground level to allow for settling. If necessary, add some backfill soil mixture to the bottom of the hole to achieve proper planting height.
Note: If the soil is poorly drained (stays constantly soggy or wet) take measures to improve drainage or select a different plant species tolerant of wet soils.
Step 5
After setting your holly in the planting hole, use one hand to hold the tree straight and your other hand to begin back-filling your soil mixture around the root ball, tamping as you go to remove air pockets. When you have filled the hole to the halfway point you can soak the soil. Then continue back-filling to the top edge of the root ball. To avoid suffocating your plant, avoid placing any soil on top of the root ball.
Step 6 (Optional)
When planting your holly tree in a site far away from a water source in well-drained soil, you can use remaining soil mixture to build a water retaining berm (catch basin / doughnut) 2 to 4 inches high or so around the outside perimeter of the planting hole. This basin will help to collect water from rainfall and irrigation, which helps to reduce the need for hand-watering. The berm can be removed after a growing season.
Step 7
Next, deeply water the planting area, including the root ball, to a depth equal to the height of the root ball. For an extra boost, you can water your newly planted holly with a solution of Root Stimulator, which stimulates early root formation and stronger root development, reduces plant shock, and promotes greener, more vigorous plants.
Step 8
To conserve moisture and suppress weed growth, apply a 1 to 2" layer of shredded or chipped wood mulch or pine straw around the planting area. Avoid using freshly chipped wood for mulch until it has cured in a pile for at least 6 months, a year is better. Avoid placing or piling mulch directly against the base of your tree as this could cause the bark to rot.
Staking a Newly Planted Holly Tree
Single Stake Method
For smaller trees, use one long stake driven firmly into the ground so that it crosses the trunk of the tree at an angle a foot or two above the ground (depending on height of tree). Use a piece of cloth or a section of rubber water hose to tie trunk loosely against the stake. Loop the cloth around the trunk of the tree and then cross the ends over one another before looping and tying it around the stake. Doing so help to keep the tree trunk from rubbing against the stake in windy weather. Avoid using metal wire as a tie as it can cut into the bark of your tree.
Triple Stake Method
For taller trees, you can drive three 18" long stakes at a 45 degree angle into the ground beyond the outside perimeter of the planting hole. Space the stakes evenly around the planting hole. Use wire or nylon string to tie from the stake to the tree. To protect the bark of your tree, make sure to run the string or wire through rubber hosing where it will come into contact with the trunk or branches. More on this just below.
To ensure your string or wires do not slide down the trunk of your tree, when tying your string or wire to the tree, you will need to tie above a branch. Otherwise your wires will slide down the trunk. To prevent damage to the bark of your tree, rubber hosepipe should be used where the wire touches the stem or branches.
Planting A Holly Tree In A Container
Holly trees growing in pots appreciate a moist, but well-drained soil. Constantly soggy soil can and often will cause root rot or other harmful or deadly plant diseases. Therefore, to ensure good drainage, use a pot with a drainage hole(s) and a quality potting soil or potting mix, or a 50/50 combination thereof, for planting. Optionally, you can also add 10 to 20% some pumice or perlite to the soil mixture to help with drainage.
Choose a container that is large enough to allow for 2 to 3 years of growth before shifting up to a larger size container. This might mean your planting pot would be 10 inches or more in diameter (width) than the root ball of your plant.
Container color will matter as well. Not only will you want to pick a color of container that compliments the foliage and berry color of your holly tree, you'll also want to pick a container that matches the style of your home or other structures and other plants in the surrounding environment.
Many nursery & garden centers offer a wide variety of containers to choose from. Before heading out to buy a container take pictures of your home and the surrounding environment. Doing so will help you to choose just the right color and style.
Container Planting Instructions
Step 1
Before filling your container with the soil mix, I recommend lining the bottom with shade cloth or a porous landscape fabric. This will keep the drain holes from becoming clogged with roots and soil. If you use gravel or other materials in the bottom of the container lay the fabric on top of it.
Step 2
To remove your holly tree from the nursery pot, firmly grasp the plant at its base and gently try to lift and remove it from the nursery pot. If the root ball is stuck in the pot use snips to cut the container away. After having removed the plant from the container, use your fingers or a claw tool to carefully loosen some feeder roots around the surface of the root ball.
Step 3
Pour a small amount of your soil mixture in the bottom of the container. Set your plant in the container and make necessary adjustments by adding or removing some soil so that the top edge of the root ball will sit approximately 1" below the rim of the container.
Step 4
Backfill with your soil mixture around the root ball, tamping as you go, until the level of potting soil is even with the top edge of root ball.
Step 5
Water thoroughly until water starts to drain from the holes in the bottom of the container. Add more soil mixture if settling occurs during watering.
Step 6 (Optional)
Apply a 1/2" layer of wood chips or sphagnum moss to soil surface to help conserve moisture. Stone mulch can also be used.