Planting & Caring For Southern Magnolias

When planted right and in the right spot, Southern Magnolia trees are exceptionally easy-to-grow in the ground or in containers.

Here's a breakdown of what you need to know...



Cultural Preferences



Soil Preferences

Southern Magnolias are easy to grow in moist but well-drained acidic to neutral soils of average fertility. Constantly soggy or wet soils can be problematic. So make sure to plant them in a well-drained site.


Testing Soil Drainage  

If you are uncertain about soil drainage in the area you intend to plant your Magnolia, 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 possibly a need to add organic matter to help retain moisture. A slower rate indicates poor draining soil and is a caution you need to improve drainage, plant in a raised mound or bed, or look for trees that are more tolerant of wet or boggy conditions.


Soil pH Preference

Southern Magnolia trees grow best in an acid to slightly alkaline soil ranging between 4.5 to 7.5 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 Southern Magnolia, 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 SulfurAluminum 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.




Light Preferences

Southern Magnolias grow best in full sun or part shade. Foliage will be more dense with more sun.




How To Plant A Southern Magnolia

Scroll down for container planting instructions


Step 1

Start by digging your planting hole at least two to three times as wide and no deeper than the root ball. 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 consider amending the native soil. When planting Southern Magnolias in dense clay or poor quality soil it is beneficial to thoroughly mix in some good organic matter such as composted cow manure, mushroom compost, sand, and/or a good planting mix at a 50/50 ratio with the soil removed from the planting hole. When planting in very sandy or quick-draining soil consider mixing in some top soil, peat moss or compost to help with moisture retention. When planting in a moist but well-drained soil of good fertility there is no need for adding a soil amendment.


Step 3

To remove your Southern Magnolia from the container it was growing in first squeeze the sides of the container to loosen root ball. Then, firmly grasp the base of the trunk and try to gently lift and remove the root ball from the container. If the root ball is stuck in the container either use a snipping tool or utility knife to cut the container away. After having removed the plant from the container, very carefully loosen some feeder roots around the surface of the root ball.


Step 4

To plant, set your Magnolia in the planting hole so that the top edge of the root ball is at or slightly above ground level (1-inch or so) 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 in the planting area is poorly drained (constantly soggy or wet) improve soil drainage or select a different plant species more tolerant of wet soils.



Step 5

After setting your Magnolia tree 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 Magnolia tree in a site site far away from a water source you can use remaining soil mixture to build a 4-5 inch high water retaining berm (catch basin / doughnut) around the outside perimeter of the planting hole. This basin will help to collect water from rainfall and irrigation often reducing the need for hand-watering. The berm can be removed after a year or so or when the tree has established itself.


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 Magnolia tree with a solution of Root Stimulator, which stimulates early root formation and stronger root development. Root Stimulator reduces plant shock and promotes greener, more vigorous plants.


Step 8

To help conserve moisture and suppress weed growth, spread a 1- to 2-inch layer of shredded or chipped wood mulch or a 3- to 4-inch layer of pine straw around the planting area. 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.



How To Plant A Magnolia Tree In A Container 


With the exception of Dwarf Southern Magnolias, such as Little Gem, most varieties of Southern Magnolias are not suitable for growing in containers over the long term...they simply grow too large. That said, they grow well in containers and eventually can be transplanted to the landscape. 

Magnolia 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 strongly suggest planting in a container that has a drainage hole(s) and using a quality potting soil. To ensure good drainage you can add 10 to 20% perlite or pumice to the soil mixture. 

Make sure to 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 shifting up to a larger size container. This might mean your planting pot would be 8 inches or more in rim diameter than the root ball of your tree. 

Note: Keep in mind the wind. When planting taller growing trees in containers, wind is always a factor. Choose a pot with a low profile and make sure to place your container where it will not be exposed to high winds. 

Container color will matter as well. Not only will you want to pick a color of container that goes well with the flower and foliage color of your Magnolia 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, we 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 place gravel or other materials in the bottom of the container lay the fabric over it. 


Step 2

To remove your Southern Magnolia from the container it was growing in first squeeze the sides of the container to loosen root ball. Then, firmly grasp the base of the trunk and try to gently lift and remove the root ball from the container. If the root ball is stuck in the container either use a snipping tool or utility knife to cut the container away. After having removed the plant from the container, very 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 the tree 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" below the rim of the container.

Step 4

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.


Step 5

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, stone mulch or sphagnum moss to soil surface for decorative purposes and to help conserve moisture.




How To Grow and Care For Southern Magnolia

Feeding - Watering - Pruning


How To Fertilize Magnolia Tree


Southern Magnolia are light feeders, however will benefit from fertilization. Feed in spring with a slow-release shrub & tree food, preferably one that contains Sulfur and/or Iron for deep greening of foliage. Alternatively, you can feed with a natural organic plant food. To avoid stimulating new growth that could be damaged by an early frost, cease fertilization two months prior to the average first frost date in your area.


In Containers

Feed Magnolia trees growing in containers as directed on the product label with a slow-release granular or water soluble fertilizer listed for use in containers.


Soil pH

Southern Magnolias grow best in an acid to slightly acid soil ranging between 4.5 to 7.5 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 Southern Magnolia, 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 SulfurAluminum 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.





How To Water A Magnolia Tree


Southern Magnolias like a moist but well-drained soil while establishing themselves, however are very drought tolerant when established. As with so many other ornamental plants, constantly soggy or wet soil conditions can be problematic. 


Tip:  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. 



At Planting Time 

Immediately after planting deep soak the soil in 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 Magnolia with a solution of Root Stimulator, which stimulates early root formation and stronger root development. Root Stimulator reduces plant shock and promotes greener, more vigorous plants.


During the First Active Growth Season

In average garden soil you should not have to water your newly planted Magnolia every day. More often than not, this causes soggy soil conditions that can lead to root rot and other plant diseases. In the absence of sufficient rainfall, water only as needed to keep the root ball and surrounding soil damp to moist. 

Keep in mind that deep soaking less frequently 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. So, be extra careful not to overwater during winter!


Thereafter

When established, Magnolia are quite drought tolerant. That said, if you see wilting new leaves or new stems wilting or bending over during a drought this could be an indicator your trees could use a good deep soaking.




How To Prune A Magnolia Tree


Southern Magnolias do not require pruning except to remove a damaged or broken branch, or a stray branch that is spoiling the form of the tree. That said, they can be pruned to form a more dense tree or for espalier (trained to grow flat against a wall). 


When to Prune

The time to prune a Magnolia is after they bloom or during the summer. Pruning them in midsummer will give them time to heal before winter.


How To Prune

Prune a Southern Magnolia only when necessary, since they can bleed from pruning wounds. Magnolias can be slow to heal and not make new growth until the second season after pruning, so avoid large cuts into old wood if possible. 

When pruning your Southern Magnolia, remove the entire twig or limb down to its base. Don't leave a stub that can produce weak stem suckers and make it easier for pests and diseases to attack the tree. Don't paint or tar pruning cuts because it interferes with the plant's own wound defense system. 

The only tool you will need for the task is a sharp pair of bypass hand pruners for branches less than 1 inch in diameter, or a lopper pruner for branches up to 1 and 1/2 inch, or a pruning saw for the largest branches. Make sure blades are sharp to leave smooth cuts that heal faster and reduce disease problems. 

Note: If you're pruning to remove a diseased branch, sterilize the pruning tools by dipping them into undiluted alcohol or a solution of 10 percent bleach.



Plant Long & Prosper!

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