Posted by Brent Wilson on 8/17/2016 to Fertilizing & Watering Tips
Arborvitae trees are exceptionally easy to grow in the ground or in containers provided they are planted right and in the right spot. These hardy and durable evergreen conifers are ideal for use in the landscape as specimens, in groupings, or as tall hedges screens and buffers.
Here's a breakdown of what you need to know regarding planting and caring for Arborvitae in the landscape and in pots...
Arborvitae adapt to a wide range of soils, including red clay, but they prefer moist, well-drained loams. They don't like an overly dry site. That said, when established they tolerate dry periods well. As with so many other ornamental plants, constantly soggy or wet soil can be problematic. So make sure to plant your Arborvitae in a well-drained site.
How To Test Soil Drainage
If you are uncertain about soil drainage in the area you intend to plant your Arborvitae, 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. A slower rate indicates poor draining soil and is a caution you might need to improve drainage, plant in a raised mound or bed, or look for plants that are more tolerant of wet or boggy conditions.
Arborvitae grow best in a slightly acid to moderately alkaline soil ranging from 6.5 to 8.0 on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0.
Testing 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, or whether or not it's suitable for growing Arborvitae, it's a good idea to test the 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?
Arborvitae will grow in full sun to part shade. For best overall performance 6 hours of direct sunlight per day is recommended.
Planting Arborvitae In The Ground
Scroll down for container planting instructions and care tips
If you are planting a smaller growing Arborvitae shrub see:
If you are planting your Aborvitae as a screen or hedge see:
Start by digging your planting hole at least two to three times as wide and as deep or not much deeper than the root ball of your Arborvitae 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.
Depending on the type, fertility and porosity of the soil in the planting area, it might be beneficial to amend the native soil. To enhance porosity and ensure good drainage, when planting in heavy clay or other compacted or poor soil it is beneficial to thoroughly mix in a good soil conditioner, planting mix, sand, and/or organic compost at a 50/50 ratio with the soil removed from the planting hole. When planting in very sandy, quick-draining soil, top soil, organic compost, or peat moss can be added to help retain moisture. When planting in fertile, loamy, well-drained moist soil there may not be a need to amend soil.
To remove your Arborvitae from the container it was growing in, firmly grasp the base of the plant and try to gently lift and remove it from its container. Avoid pulling so hard that the plant is damaged. If the root ball is stuck in the container either cut the container away or place the plant on it's side and tap on the side of the container to loosen the root ball. After having removed the rootball from the container, loosen some feeder roots around the surface of the root ball. If root bound, you can spray the sides and bottom of the root ball with a stream of water from a garden hose. This will help to wash away some soil from the exterior of the root ball making it easier to loosen roots.
If you are planting in well-drained soil set your Arborvitae in the planting hole so that the top edge of the rootball is at or slightly above ground level (1-inch or so) to allow for settling. If your soil is moderately drained, meaning it drains less than 1/2 inch per hour, the top of the root ball should be 2 to 3 inches above ground level. 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 (constantly soggy or wet) either improve drainage in the planting area or select select a different plant species that is tolerant of wet soils.
After setting your Arborvitae in the planting hole, use one hand to hold it 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. If you are planting the root ball higher than ground level taper your soil mixture gradually from the top edge of the root ball to the ground level, as shown in the planting diagram above. To avoid suffocating your plant, avoid placing any soil on top of the root ball.
Step 6 (Optional)
When planting your Arborvitae far away from a water source, and in well-drained soil, you can use remaining soil mixture to build a water retaining berm (water catch basin/doughnut) around the outside perimeter of the planting hole, as shown in the diagram above. This basin will help to collect water from rainfall and irrigation often reducing watering frequency. The berm can be removed after a growing season or two, when the plant has established itself.
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 Arborvitae with a solution of Root Stimulator, which stimulates early root formation and stronger root development, reducing plant shock and promoting greener, more vigorous plants.
Apply a 1 to 2" layer of cured, shredded or chipped wood mulch or pine straw around the planting area to conserve moisture and to suppress weed growth. As the mulch decomposes it will add vital nutrients to the soil that your plant will appreciate. Avoid the use of freshly chipped or shredded 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 plant as this could cause the bark to rot.
Planting An Arborvitae In A Pot
Arborvitae 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, I recommend using a quality potting soil or potting mix, or a 50/50 combination thereof for planting. To enhance drainage, you can also add some (10-20%) pumice or perlite to the soil mixture.
Choose a container with drainage holes at the bottom and one that is large enough to allow for 2 to 3 years of growth before having to shift up to a larger size container. This might mean your planting pot would be 5-6 inches or more in width than the root ball of your plant.
Container color will matter as well. Not only will you want to pick a container that goes well with the foliage color and texture of your plant, 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
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 stopped up with soil. If you put gravel, rocks or other materials in the bottom of the pot lay the fabric on top of it.
To remove your Arborvitae from the container it was growing in, firmly grasp the base of the plant and try to gently lift and remove it from its container. Avoid pulling so hard that the plant is damaged. If the root ball is stuck in the container either cut the container away or place the plant on it's side and tap on the side of the container to loosen the root ball. After having removed the plant from the container, loosen some feeder roots around the surface of the root ball. If root bound, you can spray the sides and bottom of the root ball with a stream of water from a garden hose. This will help to wash away some soil from the exterior of the root ball making it easier to loosen roots.
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 1/2 to 1" below the rim of the container.
Backfill with your potting soil around root ball, tamping as you go, until the level of potting soil is even with the top edge of root ball.
Water thoroughly until water starts to drain from the holes in the bottom of the container. Add more potting mix 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.
How To Care For Arborvitae
How To Fertilize Arborvitae
Arborvitae will benefit from fertilization. I feed mine in late winter with a quality slow-release shrub & tree type fertilizer or a natural or organic plant food. before fertilizing plants, carefully read and follow application instructions on product label.
Feed Arborvitae growing in pots or other types of containers with a slow-release or water-soluble plant food listed for use in containers. Read and carefully follow application instructions on product label.
Arborvitae grow best in a slightly acid to mildly alkaline soil ranging from 6.5 to 8.0 to on the pH scale. Most average garden soils fall between a pH range of 6.0 to 7.0.
Learn More: What is Soil pH and How To Adjust It?
How To Water Arborvitae
When established, Arborvitae will tolerate periods of dry weather. That said, they prefer a consistently moist soil when establishing themselves. They do not like overly dry sites or constantly soggy or wet soil, which can lead to root rot and other harmful plant diseases. So be careful not to over-water them.
At Planting Time
Immediately after planting deep soak the soil in the planting area to a depth equal to the height of the plants root ball. For an extra boost, to stimulate early root formation and stronger root development, which reduces transplant shock and promotes greener more vigorous plants, you can water you newly planted Arborvitae with a solution of Root Stimulator. When planted during the winter dormant season Arborviatae will require less water. So, be extra careful to avoid overwatering during winter.
During the First Growing Season
In average garden soil you should not have to water your newly planted Arborvitae every day. More often than not, this causes soggy soil conditions that can lead to root rot and other harmful plant diseases. In the absence of sufficient rainfall, water only as needed to keep the rootball and surrounding soil damp to moist. Keep in mind that deep soaking less frequently, allowing the soil to dry out somewhat before watering again, is much better than splashing just a little water on the plants every day. Shrubs planted during the winter dormant season, when plants are not actively growing and evaporation is much slower, will require much less water.
When established, Arborvitae will require supplemental irrigation only during prolonged periods of drought. If you see foliage drooping, or turning a lighter shade of color during dry weather, this could be a sign your plant could use a good deep soaking.
Note: When watering with an automated irrigation system it's best to set your timer to water during the early morning hours and not in the late evening or at night, which can lead to the onset of fungus and other foliar diseases. During the first few weeks after planting, check soil moisture often and adjust irrigation time if necessary to keep the soil moist, not wet.
As soil in containers dries out more quickly, you'll want to use the finger test to check soil moisture frequently until you have an idea how long it takes for the soil to dry out. When the top 1 to 2 inches of the soil is dry provide water.
How To Prune Arborvitae
Arborvitae do not require pruning, however can be sheared on occasion to maintain a more formal look. Unless you are pruning to a topiary form (poodle tier, spiral, ect), avoid pruning beyond where there is green growth on a branch.
When to Prune
Pruning or shearing of Arborvitae should be performed during late winter, before new growth begins to emerge. Selective pruning of a stray or damaged branch can be performed throughout the season.
How To Prune
For general shaping to keep the plant tidy, use a sharp pair of bypass hand pruners to cut back a branch that has outgrown and is spoiling the shape of the plant. You can use pruning shears or hedge trimmers to lightly shear the plant for a more formal look.
Note: Cease pruning 2 months prior to the average first-frost date in your area.
Plant Long & Prosper!
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